Ultrasonic surgical instrument blades

ABSTRACT

An ultrasonic surgical instrument including an ultrasonically actuated blade or end effector having a treatment portion. The blade can define a central axis and at least one axis which is transverse to the central axis, wherein the transverse axis can lie within a plane which is perpendicular, or normal, to the longitudinal axis and can define a cross-section of the treatment portion. Such a cross-section can include a central portion and a step extending from the central portion, wherein the central portion can comprise a width, and wherein the step can comprise a cutting edge. In at least one embodiment, the cutting edge can be defined by first and second surfaces which define an angle therebetween. In various embodiments, the position of the cutting edge and/or the angle between the cutting edge surfaces can be selected in order to balance the blade with respect to the transverse axis.

BACKGROUND

Ultrasonic instruments, including both hollow core and solid coreinstruments, are used for the safe and effective treatment of manymedical conditions. Ultrasonic instruments, and particularly solid coreultrasonic instruments, are advantageous because they may be used to cutand/or coagulate organic tissue using energy in the form of mechanicalvibrations transmitted to a surgical end effector at ultrasonicfrequencies. Ultrasonic vibrations, when transmitted to organic tissueat suitable energy levels and using a suitable end effector, may be usedto cut, dissect, elevate or cauterize tissue or to separate muscletissue off bone. Ultrasonic instruments utilizing solid core technologyare particularly advantageous because of the amount of ultrasonic energythat may be transmitted from the ultrasonic transducer, through awaveguide, to the surgical end effector. Such instruments may be usedfor open procedures or minimally invasive procedures, such as endoscopicor laparoscopic procedures, wherein the end effector is passed through atrocar to reach the surgical site.

Activating or exciting the end effector (e.g., cutting blade) of suchinstruments at ultrasonic frequencies induces longitudinal vibratorymovement that generates localized heat within adjacent tissue,facilitating both cutting and coagulation. Because of the nature ofultrasonic instruments, a particular ultrasonically actuated endeffector may be designed to perform numerous functions, including, forexample, cutting and coagulation.

Ultrasonic vibration is induced in the surgical end effector byelectrically exciting a transducer, for example. The transducer may beconstructed of one or more piezoelectric or magnetostrictive elements inthe instrument hand piece. Vibrations generated by the transducersection are transmitted to the surgical end effector via an ultrasonicwaveguide extending from the transducer section to the surgical endeffector. The waveguides and end effectors are designed to resonate atthe same frequency as the transducer. Therefore, when an end effector isattached to a transducer the overall system frequency is the samefrequency as the transducer itself.

The amplitude of the longitudinal ultrasonic vibration at the tip, d, ofthe end effector behaves as a simple sinusoid at the resonant frequencyas given by:

d=A sin(ωt)

where:ω=the radian frequency which equals 2π times the cyclic frequency, f,andA=the zero-to-peak amplitude.The longitudinal excursion is defined as the peak-to-peak (p-t-p)amplitude, which is just twice the amplitude of the sine wave or 2 A.

The shape of an ultrasonic surgical blade or end-effector used in anultrasonic surgical instrument can define at least four importantaspects of the instrument. These are: (1) the visibility of theend-effector and its relative position in the surgical field, (2) theability of the end-effector to access or approach targeted tissue, (3)the manner in which ultrasonic energy is coupled to tissue for cuttingand coagulation, and (4) the manner in which tissue can be manipulatedwith the ultrasonically inactive end-effector. It would be advantageousto provide an improved ultrasonic surgical instrument blade orend-effector optimizing at least these four aspects of the instrument.

However, as features are added to an ultrasonic surgical instrumentblade to achieve the above-listed aspects, the shape of the blade istypically altered which creates asymmetries therein and causes the bladeto become unbalanced, meaning that the blade can have the tendency tovibrate in directions other than the longitudinal direction along thelength of the instrument, such as transverse directions. Substantialtransverse motion in the blade and/or waveguide may lead to excess heatgeneration and/or premature stress failure therein. Long, thinultrasonic waveguides, such as those used in instruments for minimallyinvasive surgery, are particularly susceptible to transverse vibrationsintroduced by imbalances, or asymmetries, in the end effector.

U.S. Pat. No. 6,283,981, which issued on Sep. 4, 2001 and is entitledMETHOD OF BALANCING ASYMMETRIC ULTRASONIC SURGICAL BLADES, U.S. Pat. No.6,309,400, which issued on Oct. 30, 2001 and is entitled CURVEDULTRASONIC BLADE HAVING A TRAPEZOIDAL CROSS SECTION, and U.S. Pat. No.6,436,115, which issued on Aug. 20, 2002 and is entitled BALANCEDULTRASONIC BLADE INCLUDING A PLURALITY OF BALANCE ASYMMETRIES, thedisclosures of which are hereby incorporated by reference herein,address balancing blades having asymmetries within a treatment portionof the blade by utilizing asymmetries within an adjacent balanceportion. While such approaches have proven eminently successful, thereare some applications where balancing may be desirable within thetreatment, or functional, portion of a blade.

Solid core ultrasonic surgical instruments may be divided into twotypes, single element end effector devices and multiple-element endeffector. Single element end effector devices include instruments suchas scalpels, and ball coagulators. Single-element end effectorinstruments have limited ability to apply blade-to-tissue pressure whenthe tissue is soft and loosely supported. Substantial pressure may benecessary to effectively couple ultrasonic energy to the tissue. Thisinability to grasp the tissue results in a further inability to fullycoat tissue surfaces while applying ultrasonic energy, leading toless-than-desired hemostasis and tissue joining. The use ofmultiple-element end effectors such as clamping coagulators includes amechanism to press tissue against an ultrasonic blade that can overcomethese deficiencies.

Ultrasonic clamp coagulators provide an improved ultrasonic surgicalinstrument for cutting/coagulating tissue, particularly loose andunsupported tissue, wherein the ultrasonic blade is employed inconjunction with a clamp for applying a compressive or biasing force tothe tissue, whereby faster coagulation and cutting of the tissue, withless attenuation of blade motion, are achieved.

Surgical elevators are instruments used to help facilitate the elevationand removal of soft tissue during surgery. Surgical elevators aregenerally employed to separate muscle from bone. Cobb or curette typesurgical elevators and used in spine surgery, especially to assist inposterior access in removing muscle tissue from bone. To remove muscletissue from bone using conventional surgical elevators, the surgeon mustexert a significant amount of force. This may cause premature fatigue.Also, using significant force on a conventional surgical elevator duringthis technique may increase the likelihood of error and unwanted tissuedamage.

It would be desirable to provide an ultrasonic instrument comprising asurgical elevator blade to remove soft tissue such as muscle from boneand to perform additional surgical functions as well. Also, becauseultrasonic frequencies induce longitudinal vibratory movements andgenerate localized heat within adjacent tissue it would be desirable toprovide a protective material for the surgical elevator of suchultrasonic instrument. The protective material may reduce thepossibility of blade breakage when in contact with bone or metalretractors and may decrease thermal spread from the back edge of theblade.

SUMMARY

In one general aspect, the various embodiments are directed to anultrasonic surgical instrument that comprises a transducer configured toproduce vibrations at a predetermined frequency. The transducer isconfigured to produce vibrations along a longitudinal axis at apredetermined frequency. An ultrasonic blade extends along thelongitudinal axis and is coupled to the transducer. The ultrasonic bladeincludes a body having a proximal end and a distal end. The distal endis movable relative to the longitudinal axis by the vibrations producedby the transducer. The body includes a treatment region that extendsfrom the proximal end to the distal end. The body includes asubstantially flat broad top surface, a bottom surface, and a neckportion protruding from the proximal end adapted to couple to thetransducer.

In at least one form of the invention, an ultrasonic surgical instrumentcan include an ultrasonically actuated blade or end effector having atreatment portion. In various embodiments, the blade can define alongitudinal axis and at least one axis which is transverse to thelongitudinal axis. In at least one such embodiment, the transverse axiscan lie within a plane which is perpendicular, or normal, to thelongitudinal axis and can define a cross-section of the treatmentportion. In various embodiments, such a cross-section can include acentral portion and a step, wherein the step can extend from the centralportion, wherein the central portion can comprise a width, and whereinthe step can comprise a cutting edge. In at least one embodiment, thecutting edge can be defined by first and second surfaces which define anangle therebetween. In various embodiments, the position of the cuttingedge and/or the angle between the cutting edge surfaces, for example,can be selected in order to balance the blade with respect to thetransverse axis.

FIGURES

The novel features of the various embodiments are set forth withparticularity in the appended claims. The various embodiments, however,both as to organization and methods of operation, together with furtherobjects and advantages thereof, may best be understood by reference tothe following description, taken in conjunction with the accompanyingdrawings as follows.

FIG. 1 illustrates one embodiment of an ultrasonic system.

FIG. 2 illustrates one embodiment of a connection union/joint for anultrasonic instrument.

FIG. 3 illustrates an exploded perspective view of one embodiment of asterile ultrasonic surgical instrument.

FIGS. 4-7 illustrate one embodiment of an ultrasonic blade, where:

FIG. 4 is a side view of one embodiment of an ultrasonic blade;

FIG. 5 is a top view of the ultrasonic blade shown in FIG. 4;

FIG. 6 is a cross-sectional view of the ultrasonic blade taken alongline 6-6 in FIG. 4; and

FIG. 7 is a top perspective view of the ultrasonic blade shown in FIG.4.

FIGS. 8-11 illustrate one embodiment of an ultrasonic blade, where:

FIG. 8 is a side view of one embodiment of an ultrasonic blade;

FIG. 9 is a top view of the ultrasonic blade shown in FIG. 8;

FIG. 10 is a cross-sectional view of the ultrasonic blade taken alongline 10-10 in FIG. 8; and

FIG. 11 is a top perspective view of the ultrasonic blade shown in FIG.8.

FIGS. 12-15 illustrate one embodiment of an ultrasonic blade, where:

FIG. 12 is a side view of one embodiment of an ultrasonic blade;

FIG. 13 is a top view of the ultrasonic blade shown in FIG. 12;

FIG. 14 is a cross-sectional view of the ultrasonic blade taken alongline 14-14 in FIG. 12; and

FIG. 15 is a top perspective view of the ultrasonic blade shown in FIG.12.

FIGS. 16-19 illustrate one embodiment of an ultrasonic blade, where:

FIG. 16 is a side view of one embodiment of an ultrasonic blade;

FIG. 17 is a top view of the ultrasonic blade shown in FIG. 16;

FIG. 18 is an end-sectional view of the ultrasonic blade taken alongline 18-18 in FIG. 16; and

FIG. 19 is a top perspective view of the ultrasonic blade shown in FIG.16.

FIG. 20 is a top perspective view of one embodiment of an ultrasonicblade.

FIG. 21 illustrates a use of one embodiment of the ultrasonic bladeshown in FIG. 20.

FIGS. 22-24 illustrate one embodiment of an ultrasonic blade comprisinga protective sheath, where:

FIG. 22 illustrates a partial cross-sectional view of one embodiment ofan ultrasonic blade comprising a protective sheath taken along thelongitudinal axis;

FIG. 23 is a bottom view of the ultrasonic blade taken along line 23-23in FIG. 22; and

FIG. 24 is a cross-sectional view of the ultrasonic blade and theprotective sheath shown in FIG. 22.

FIG. 25 illustrates a use of one embodiment of an ultrasonic surgicalinstrument removing muscle tissue from bone.

FIG. 26 illustrates a use one embodiment of the ultrasonic surgicalblade shown in FIGS. 20, 21 comprising one embodiment of a protectivesheath.

FIGS. 27-31 illustrate one embodiment of an ultrasonic surgicalinstrument comprising an end effector, where:

FIG. 27 is a top perspective view of one embodiment of an ultrasonicsurgical instrument;

FIG. 28 is a cross-sectional view of the ultrasonic surgical instrumentshown in FIG. 27 taken along the longitudinal axis of the ultrasonicsurgical instrument shown in FIG. 27;

FIG. 29 is a bottom view of the ultrasonic surgical instrument takenalong lines 29-29 in FIG. 28;

FIG. 30 is a cross-sectional view of the ultrasonic surgical instrumenttaken along lines 30-30 in FIG. 28; and

FIG. 31 is cross-sectional view of the ultrasonic surgical instrumenttaken along lines 31-31 in FIG. 28.

FIGS. 32-35 are cross-sectional views of various embodiments ofultrasonic surgical instruments taken along the longitudinal axis.

FIGS. 36-37 are cross-sectional views of one embodiment of an ultrasonicsurgical instrument taken along the longitudinal axis.

FIGS. 38-39 are cross-sectional views of one embodiment of an ultrasonicsurgical instrument taken along the longitudinal axis.

FIG. 40 is cross-sectional view of one embodiment of an ultrasonicsurgical instrument taken along the longitudinal axis.

FIGS. 41-43 illustrate one embodiment of an ultrasonic system, where:

FIG. 41 is a side view of one embodiment of the ultrasonic system;

FIG. 42 is a cross-sectional side view of the ultrasonic system shown inFIG. 41 and a cross-sectional view of various tube assemblies to couplethe hand piece housing with an end effector;

FIG. 43 is a bottom cross-sectional view of the ultrasonic instrumentshown in FIG. 41.

FIGS. 44-51 illustrate one embodiment of an ultrasonic system, where:

FIG. 44 is a side view of one embodiment of a ultrasonic instrument witha deployable protective sheath in a stowed or retracted position;

FIG. 45 is a top view of the ultrasonic instrument with the deployableprotective sheath in the stowed or retracted position taken along line45-45 in FIG. 44;

FIG. 46 is a side view of the ultrasonic instrument shown in FIG. 44with the deployable protective sheath in a deployed position;

FIG. 47 is a top view of the ultrasonic instrument in the deployedposition taken along line 47-47 in FIG. 46;

FIG. 48 is a more detailed side view of the ultrasonic instrument shownin FIG. 44 with the deployable protective sheath in a stowed orretracted position;

FIG. 49 is a more detailed top view of the ultrasonic instrument shownin FIG. 45 with the protective sheath in the stowed or retractedposition taken along line 49-49 in FIG. 48;

FIG. 50 is a more detailed side view of the ultrasonic instrument shownin FIG. 46 with the deployable protective sheath in a deployed position;and

FIG. 51 is a more detailed top view of the ultrasonic instrument shownin FIG. 47 in the deployed position taken along line 51-51 in FIG. 50.

FIGS. 52-55 illustrate one embodiment of an ultrasonic surgicalinstrument comprising an end effector, where:

FIG. 52 is a top perspective view of one embodiment of an ultrasonicsurgical instrument;

FIG. 53 is a partial cross-sectional view of the ultrasonic surgicalinstrument shown in FIG. 52 taken along the longitudinal axis of theultrasonic surgical instrument;

FIG. 54 is a cross-sectional view of the ultrasonic surgical instrumenttaken along lines 54-54 shown in FIG. 53; and

FIG. 55 is a top view of the ultrasonic surgical instrument.

FIGS. 56-59 illustrate one embodiment of an ultrasonic blade, where:

FIG. 56 is a side view of one embodiment of an ultrasonic blade;

FIG. 57 is a top view of the ultrasonic blade shown in FIG. 56;

FIG. 58 is a cross-sectional view of the ultrasonic blade taken alongline 58-58 in FIG. 57; and

FIG. 59 is a top perspective view of the ultrasonic blade shown in FIG.56.

FIG. 60 is a schematic of parameters of a cross-section of a blade whichcan be used to balance the blade.

FIG. 60A is an additional schematic of the cross-section of FIG. 60

FIG. 61 is a cross-sectional view of an ultrasonic blade.

FIG. 62 is a cross-sectional view of another ultrasonic blade.

FIG. 63 is a cross-sectional view of an additional ultrasonic blade.

FIG. 64 is a cross-sectional view of a further ultrasonic blade.

DESCRIPTION

Before explaining the various embodiments in detail, it should be notedthat the embodiments are not limited in its application or use to thedetails of construction and arrangement of parts illustrated in theaccompanying drawings and description. The illustrative embodiments maybe implemented or incorporated in other embodiments, variations andmodifications, and may be practiced or carried out in various ways. Forexample, the surgical instruments and blade configurations disclosedbelow are illustrative only and not meant to limit the scope orapplication thereof. Furthermore, unless otherwise indicated, the termsand expressions employed herein have been chosen for the purpose ofdescribing the illustrative embodiments for the convenience of thereader and are not to limit the scope thereof.

The various embodiments relate, in general, to ultrasonic surgicalblades for use in surgical instruments and, more particularly, to anultrasonic surgical blade with improved elevator, cutting andcoagulation features and to an ultrasonic blade comprising a protectivesheath on a portion thereof. The various embodiments relate, in general,to ultrasonic surgical blades and instruments for improved bone andtissue removal, aspiration, and coagulation features. A blade accordingto various embodiments is of particular benefit, among others, inorthopedic procedures wherein it is desirable to remove cortical boneand/or tissue while controlling bleeding for removing muscle tissue frombone, due to its cutting and coagulation characteristics. The blade,however, may be useful for general soft tissue cutting and coagulation.The blade may be straight or curved, and useful for either open orlaparoscopic applications. A blade according to various embodiments maybe useful in spine surgery, especially to assist in posterior access inremoving muscle from bone. A blade according to the various embodimentsmay reduce the user force required to remove muscle from bone and, inone embodiment, may be useful to simultaneously hemostatically seal orcauterize the tissue. Reducing the force to operate the surgicalinstrument may reduce user fatigue, improve precision and reduceunwanted tissue damage. A variety of different blade configurations aredisclosed which may be useful for both open and laparoscopicapplications.

Examples of ultrasonic surgical instruments are disclosed in U.S. Pat.Nos. 5,322,055 and 5,954,736 and in combination with ultrasonic bladesand surgical instruments disclosed in U.S. Pat. Nos. 6,309,400 B2,6,278,218B1, 6,283,981 B1, and 6,325,811 B1, for example, areincorporated herein by reference in their entirety. Also incorporated byreference in its entirety is commonly-owned, co-pending U.S. patentapplication Ser. No. 11/726,625, entitled ULTRASONIC SURGICALINSTRUMENTS, filed on Mar. 22, 2007. Some of these references discloseultrasonic surgical instrument design and blade designs where alongitudinal node of the blade is excited. Because of asymmetry orasymmetries, these blades exhibit transverse and/or torsional motionwhere the characteristic “wavelength” of this non-longitudinal motion isless than that of the general longitudinal motion of the blade and itsextender portion. Therefore, the wave shape of the non-longitudinalmotion will present nodal positions of transverse/torsional motion alongthe tissue effector while the net motion of the active blade along itstissue effector is non-zero (i.e. will have at least longitudinal motionalong the length extending from its distal end, an antinode oflongitudinal motion, to the first nodal position of longitudinal motionthat is proximal to the tissue effector portion). Certain exemplaryembodiments will now be described to provide an overall understanding ofthe principles of the structure, function, manufacture, and use of thedevices and methods disclosed herein. One or more examples of theseembodiments are illustrated in the accompanying drawings. Those ofordinary skill in the art will understand that the devices and methodsspecifically described herein and illustrated in the accompanyingdrawings are non-limiting exemplary embodiments and that the scope ofthe various embodiments is defined solely by the claims. The featuresillustrated or described in connection with one exemplary embodiment maybe combined with the features of other embodiments. Such modificationsand variations are intended to be included within the scope of theclaims.

FIG. 1 illustrates one embodiment of an ultrasonic system 10. Oneembodiment of the ultrasonic system 10 comprises an ultrasonic signalgenerator 12 coupled to an ultrasonic transducer 14, a hand pieceassembly 60 comprising a hand piece housing 16, and an end effector 50.The ultrasonic transducer 14, which is known as a “Langevin stack”,generally includes a transduction portion 18, a first resonator orend-bell 20, and a second resonator or fore-bell 22, and ancillarycomponents. The ultrasonic transducer 14 is preferably an integralnumber of one-half system wavelengths (nλ/2) in length as will bedescribed in more detail later. An acoustic assembly 24 includes theultrasonic transducer 14, a mount 26, a velocity transformer 28, and asurface 30.

It will be appreciated that the terms “proximal” and “distal” are usedherein with reference to a clinician gripping the hand piece assembly60. Thus, the end effector 50 is distal with respect to the moreproximal hand piece assembly 60. It will be further appreciated that,for convenience and clarity, spatial terms such as “top” and “bottom”also are used herein with respect to the clinician gripping the handpiece assembly 60. However, surgical instruments are used in manyorientations and positions, and these terms are not intended to belimiting and absolute.

The distal end of the end-bell 20 is connected to the proximal end ofthe transduction portion 18, and the proximal end of the fore-bell 22 isconnected to the distal end of the transduction portion 18. Thefore-bell 22 and the end-bell 20 have a length determined by a number ofvariables, including the thickness of the transduction portion 18, thedensity and modulus of elasticity of the material used to manufacturethe end-bell 20 and the fore-bell 22, and the resonant frequency of theultrasonic transducer 14. The fore-bell 22 may be tapered inwardly fromits proximal end to its distal end to amplify the ultrasonic vibrationamplitude as the velocity transformer 28, or alternately may have noamplification. A suitable vibrational frequency range may be about 20 Hzto 120 kHz and a well-suited vibrational frequency range may be about30-70 kHz and one example operational vibrational frequency may beapproximately 55.5 kHz.

Piezoelectric elements 32 may be fabricated from any suitable material,such as, for example, lead zirconate-titanate, lead meta-niobate, leadtitanate, or other piezoelectric crystal material. Each of positiveelectrodes 34, negative electrodes 36, and the piezoelectric elements 32has a bore extending through the center. The positive and negativeelectrodes 34 and 36 are electrically coupled to wires 38 and 40,respectively. The wires 38 and 40 are encased within a cable 42 andelectrically connectable to the ultrasonic signal generator 12 of theultrasonic system 10.

The ultrasonic transducer 14 of the acoustic assembly 24 converts theelectrical signal from the ultrasonic signal generator 12 intomechanical energy that results in primarily longitudinal vibratorymotion of the ultrasonic transducer 24 and the end effector 50 atultrasonic frequencies. A suitable generator is available as modelnumber GEN01, from Ethicon Endo-Surgery, Inc., Cincinnati, Ohio. Whenthe acoustic assembly 24 is energized, a vibratory motion standing waveis generated through the acoustic assembly 24. The amplitude of thevibratory motion at any point along the acoustic assembly 24 may dependupon the location along the acoustic assembly 24 at which the vibratorymotion is measured. A minimum or zero crossing in the vibratory motionstanding wave is generally referred to as a node (i.e., where motion isusually minimal), and an absolute value maximum or peak in the standingwave is generally referred to as an anti-node (i.e., where motion isusually maximal). The distance between an anti-node and its nearest nodeis one-quarter wavelength (λ/4).

The wires 38 and 40 transmit an electrical signal from the ultrasonicsignal generator 12 to the positive electrodes 34 and the negativeelectrodes 36. The piezoelectric elements 32 are energized by theelectrical signal supplied from the ultrasonic signal generator 12 inresponse to a foot switch 44 to produce an acoustic standing wave in theacoustic assembly 24. The electrical signal causes disturbances in thepiezoelectric elements 32 in the form of repeated small displacementsresulting in large compression forces within the material. The repeatedsmall displacements cause the piezoelectric elements 32 to expand andcontract in a continuous manner along the axis of the voltage gradient,producing longitudinal waves of ultrasonic energy. The ultrasonic energyis transmitted through the acoustic assembly 24 to the end effector 50via a an ultrasonic transmission waveguide 104.

In order for the acoustic assembly 24 to deliver energy to the endeffector 50, all components of the acoustic assembly 24 must beacoustically coupled to the end effector 50. The distal end of theultrasonic transducer 14 may be acoustically coupled at the surface 30to the proximal end of the ultrasonic transmission waveguide 104 by athreaded connection such as a stud 48.

The components of the acoustic assembly 24 are preferably acousticallytuned such that the length of any assembly is an integral number ofone-half wavelengths (nλ/2), where the wavelength λ is the wavelength ofa pre-selected or operating longitudinal vibration drive frequency f_(d)of the acoustic assembly 24, and where n is any positive integer. It isalso contemplated that the acoustic assembly 24 may incorporate anysuitable arrangement of acoustic elements.

The ultrasonic end effector 50 may have a length substantially equal toan integral multiple of one-half system wavelengths (λ/2). A distal end52 of the ultrasonic end effector 50 may be disposed near an antinode inorder to provide the maximum longitudinal excursion of the distal end.When the transducer assembly is energized, the distal end 52 of theultrasonic end effector 50 may be configured to move in the range of,for example, approximately 10 to 500 microns peak-to-peak, andpreferably in the range of about 30 to 150 microns at a predeterminedvibrational frequency.

The ultrasonic end effector 50 may be coupled to the ultrasonictransmission waveguide 104. The ultrasonic end effector 50 and theultrasonic transmission guide 104 as illustrated are formed as a singleunit construction from a material suitable for transmission ofultrasonic energy such as, for example, Ti6Al4V (an alloy of Titaniumincluding Aluminum and Vanadium), Aluminum, Stainless Steel, or otherknown materials. Alternately, the ultrasonic end effector 50 may beseparable (and of differing composition) from the ultrasonictransmission waveguide 104, and coupled by, for example, a stud, weld,glue, quick connect, or other suitable known methods. The ultrasonictransmission waveguide 104 may have a length substantially equal to anintegral number of one-half system wavelengths (λ/2), for example. Theultrasonic transmission waveguide 104 may be preferably fabricated froma solid core shaft constructed out of material that propagatesultrasonic energy efficiently, such as titanium alloy (i.e., Ti-6Al-4V)or an aluminum alloy, for example.

The ultrasonic transmission waveguide 104 comprises a longitudinallyprojecting attachment post 54 at a proximal end to couple to the surface30 of the ultrasonic transmission waveguide 104 by a threaded connectionsuch as the stud 48. In the embodiment illustrated in FIG. 1, theultrasonic transmission waveguide 104 comprises a plurality ofstabilizing silicone rings or compliant supports 56 positioned at aplurality of nodes. The silicone rings 56 dampen undesirable vibrationand isolate the ultrasonic energy from a removable sheath 58 assuringthe flow of ultrasonic energy in a longitudinal direction to the distalend 52 of the end effector 50 with maximum efficiency.

As shown in FIG. 1, the removable sheath 58 is coupled to the distal endof the handpiece assembly 60. The sheath 58 generally includes anadapter or nose cone 62 and an elongated tubular member 64. The tubularmember 64 is attached to the adapter 62 and has an opening extendinglongitudinally therethrough. The sheath 58 may be threaded or snappedonto the distal end of the housing 16. The ultrasonic transmissionwaveguide 104 extends through the opening of the tubular member 64 andthe silicone rings 56 isolate the ultrasonic transmission waveguide 104therein.

The adapter 62 of the sheath 58 is preferably constructed from Ultem®,and the tubular member 64 is fabricated from stainless steel.Alternatively, the ultrasonic transmission waveguide 104 may havepolymeric material surrounding it to isolate it from outside contact.

The distal end of the ultrasonic transmission waveguide 104 may becoupled to the proximal end of the end effector 50 by an internalthreaded connection, preferably at or near an antinode. It iscontemplated that the end effector 50 may be attached to the ultrasonictransmission waveguide 104 by any suitable means, such as a welded jointor the like. Although the end effector 50 may be detachable from theultrasonic transmission waveguide 104, it is also contemplated that theend effector 50 and the ultrasonic transmission waveguide 104 may beformed as a single unitary piece.

FIG. 2 illustrates one embodiment of a connection union/joint 70 for anultrasonic instrument. The connection union/joint 70 may be formedbetween the attachment post 54 of the ultrasonic transmission waveguide104 and the surface 30 of the velocity transformer 28 at the distal endof the acoustic assembly 24. The proximal end of the attachment post 54comprises a female threaded substantially cylindrical recess 66 toreceive a portion of the threaded stud 48 therein. The distal end of thevelocity transformer 28 also may comprise a female threadedsubstantially cylindrical recess 68 to receive a portion of the threadedstud 40. The recesses 66, 68 are substantially circumferentially andlongitudinally aligned.

FIG. 3 illustrates an exploded perspective view of one embodiment of asterile ultrasonic surgical instrument 100. The ultrasonic surgicalinstrument 100 may be employed with the above-described ultrasonicsystem 10. However, as described herein, those of ordinary skill in theart will understand that the various embodiments of the ultrasonicsurgical instruments disclosed herein as well as any equivalentstructures thereof could conceivably be effectively used in connectionwith other known ultrasonic surgical instruments without departing fromthe scope thereof. Thus, the protection afforded to the variousultrasonic surgical blade embodiments disclosed herein should not belimited to use only in connection with the exemplary ultrasonic surgicalinstrument described above.

The ultrasonic surgical instrument 100 may be sterilized by methodsknown in the art such as, for example, gamma radiation sterilization,Ethelyne Oxide processes, autoclaving, soaking in sterilization liquid,or other known processes. In the illustrated embodiment, an ultrasonictransmission assembly 102 includes an ultrasonic end effector, thegenerally designated ultrasonic end effector 50, and the ultrasonictransmission waveguide 104. The ultrasonic end effector 50 and theultrasonic transmission waveguide 104 are illustrated as a single unitconstruction from a material suitable for transmission of ultrasonicenergy such as, for example, Ti6Al4V (an alloy of Titanium includingAluminum and Vanadium), Aluminum, Stainless Steel, or other knownmaterials. Alternately, the ultrasonic end effector 50 may be separable(and of differing composition) from the ultrasonic transmissionwaveguide 104, and coupled by, for example, a stud, weld, glue, quickconnect, or other known methods. The ultrasonic transmission waveguide104 may have a length substantially equal to an integral number ofone-half system wavelengths (nλ/2), for example. The ultrasonictransmission waveguide 104 may be preferably fabricated from a solidcore shaft constructed out of material that propagates ultrasonic energyefficiently, such as titanium alloy (i.e., Ti-6Al-4V) or an aluminumalloy, for example.

In the embodiment illustrated in FIG. 3, the ultrasonic transmissionwaveguide 104 is positioned in an outer sheath 106 by a mounting O-ring108 and a sealing ring 110. One or more additional dampers or supportmembers (not shown) also may be included along the ultrasonictransmission waveguide 104. The ultrasonic transmission waveguide 104 isaffixed to the outer sheath 106 by a mounting pin 112 that passesthrough mounting holes 114 in the outer sheath 106 and a mounting slot116 in the ultrasonic transmission waveguide 104.

FIGS. 4-19 illustrate various embodiments of ultrasonic blades, whichmay be considered different embodiments of the end effector 50 and aregenerally well-suited for cutting, coagulating, and reshaping tissue. Invarious embodiments, the ultrasonic blades may be configured asultrasonic surgical elevator blades that are well-suited for separatingmuscle from bone, for example. The ultrasonic blades may be employed inthe above-described ultrasonic surgical instruments 10, 100. Embodimentsof the ultrasonic blades may be suitable in spine surgery, and moreparticularly, to assist in posterior access in removing muscle tissuefrom bone and coagulating the tissue. Accordingly, the ultrasonic bladesmay be employed to simultaneously reshape or remove muscle tissue frombone and to hemostatically seal the tissue as it is removed from thebone. The ultrasonic energy assists the cutting action of the ultrasonicblade and reduces the force required by a surgeon during an operationand thereby reduces surgeon fatigue, improves precision, and reducesunwanted tissue damage. The embodiments, however, are not limited inthis context. Those skilled in the art will appreciate that although thevarious embodiments of the ultrasonic blades are well-suited forcutting, coagulating, and reshaping tissue, e.g., to separate muscletissue from bone, these ultrasonic blades are multifunctional and may beemployed in multiple numerous applications.

FIGS. 4-7 illustrate one embodiment of an ultrasonic blade 120. Theultrasonic blade 120 is generally well-suited for cutting, coagulating,and reshaping tissue. In one embodiment the ultrasonic blade 120 may beconfigured as an ultrasonic surgical elevator blade generallywell-suited to separate muscle tissue from bone. Nevertheless, theultrasonic blade 120 may be employed in various other therapeuticprocedures. FIG. 4 is a side view of the ultrasonic blade 120. FIG. 5 isa top view of the ultrasonic blade 120. FIG. 6 is a cross-sectional viewof the ultrasonic blade 120 taken along line 6-6 in FIG. 4. FIG. 7 is atop perspective view of the ultrasonic blade 120.

In the embodiment illustrated in FIGS. 4-7, the ultrasonic blade 120comprises a blade body 122 having a generally flat top surface 124 thatis substantially arcuate about a first axis 121 and a smooth generallyround bottom surface 126 that is substantially arcuate about a secondaxis 123. As shown in the cross-sectional view of FIG. 6, the topsurface 124 is generally flat and the bottom surface 126 issubstantially arcuate with respect to a third axis 125. The blade body122 extends along a longitudinal central axis 127. The blade body 122may comprise a substantially elongated treatment region, generallydesignated as 128, and a neck or transition portion 130 that protrudesfrom a proximal end 132 of the treatment region 128. The neck portion130 may be attached to the ultrasonic transmission waveguide 104 by astud, weld, glue, quick connect, or other known attachment methods, forexample. In alternative embodiments, the ultrasonic blade 120 and theultrasonic transmission waveguide 104 may be formed as a single unitarybody. In either configuration, the ultrasonic transmission waveguide 104amplifies the mechanical vibrations transmitted to the ultrasonic blade120 as is well known in the art. The ultrasonic blade 120 is adapted tocouple to the ultrasonic surgical instrument 100, which may be employedwith the above-described ultrasonic surgical instruments 10, 100.

The ultrasonic blade 120 comprises a treatment region 128 to effecttissue, such as, for example, cut, coagulate, reshape, scrape, andremove tissue. The treatment region 128 comprises the top surface 124which is substantially arcuate about the first axis 121 and the smoothbottom surface 126 which is substantially arcuate about the second axis123. As shown in the cross-sectional view in FIG. 6, the treatmentregion 128 the top surface 124 is generally flat and the bottom surface126 is substantially arcuate about the third axis 125. A distal end 134of the treatment region 128 also comprises a substantially flat tip witha cutting edge 136. The blade 120 and the distal cutting edge 136 definea broad top surface 124 for effecting tissue. The bottom surface 126 maybe a surface for bone contact and atraumatic use along the bone regionconfigured to prevent the cutting edge 136 from cutting into bonetissue. Due to its arcuate shape the bottom surface 126 may be employedto coagulate tissue. The top surface 124 of the blade 120 has a width“W” that is substantially greater than a thickness “T” of the blade 120.Additional cutting edges 138 may be positioned laterally along bothsides of the treatment region 128. In one embodiment, the cutting edges138 extend from the proximal end 132 to the distal end 134 of thetreatment region 128. In one example, the flat tip cutting edge 136 orthe lateral cutting edges 138 of the ultrasonic blade 120 are suitableto remove muscle tissue from bone while the smooth generally roundsubstantially arcuate bottom surface 126 acts as an atraumatic surfacethat glides against the bone.

The ultrasonic blade 120 may be fabricated from a material suitable fortransmission of ultrasonic energy such as, for example, Ti6Al4V (analloy of Titanium including Aluminum and Vanadium), Aluminum, StainlessSteel, or other known materials.

FIGS. 8-11 illustrate one embodiment of an ultrasonic blade 150. Theultrasonic blade 150 is generally well-suited for cutting, coagulating,and reshaping tissue. In one embodiment the ultrasonic blade 150 may beconfigured as an ultrasonic surgical elevator blade generallywell-suited to separate muscle tissue from bone. Nevertheless, theultrasonic blade 150 may be employed in various other therapeuticprocedures. FIG. 8 is a side view of the ultrasonic blade 150. FIG. 9 isa top view of the ultrasonic blade 150. FIG. 10 is a cross-sectionalview of the ultrasonic blade 150 taken along line 10-10 in FIG. 8. FIG.11 is a top perspective view of the ultrasonic blade 150.

In the embodiment illustrated in FIGS. 8-11, the ultrasonic blade 150comprises a blade body 152 having a generally flat planar top surface154 and a smooth substantially arcuate bottom surface 156. The top andbottom surfaces 154, 56 extend along the longitudinal central axis 127.As shown in the cross-sectional view of FIG. 10, the top surface 154 isgenerally flat and planar and the bottom surface 156 is substantiallyarcuate about axis 129. The blade body 152 may comprise a substantiallyelongated treatment region, generally designated as 158, and a neck ortransition portion 160 that protrudes from a proximal end 132 of thetreatment region 158. The neck portion 160 may be attached to theultrasonic transmission waveguide 104 by a stud, weld, glue, quickconnect, or other known attachment methods, for example. In alternativeembodiments, the ultrasonic blade 150 and the waveguide 104 may beformed as a single unitary body. In either configuration, the ultrasonictransmission waveguide 104 amplifies the mechanical vibrationstransmitted to the ultrasonic blade 150 as is well known in the art. Theultrasonic blade 150 is adapted to couple to the ultrasonic surgicalinstrument 100, which may be coupled to above-described ultrasonicsystem 10. In one embodiment, the ultrasonic blade 150 and theultrasonic transmission waveguide 104 may be formed as a single unitarybody.

The ultrasonic blade 150 comprises the substantially straight planartreatment region 158 to effect tissue. The treatment region 158comprises the generally flat planar top surface 154 and the smoothsubstantially arcuate bottom surface 156. The bottom surface 156comprises a smooth atraumatic surface 162 that is substantially arcuateabout axis 131 at a distal end 134 of the treatment region 158 for bonecontact and atraumatic use along the bone region. The distal end 134 ofthe treatment region 158 also comprises a substantially flat tip with adistal cutting edge 166. The atraumatic surface 162 is configured toprevent the distal cutting edge 166 from cutting into bone tissue. Theatraumatic surface 162 extends from the bottom surface 156 to the topsurface 154 and is intended to contact and slidingly engage the bone asthe cutting edge 166 removes muscle tissue from the bone without cuttinginto bone tissue. A cutting edge 168 is positioned laterally along oneside of the treatment region 158. The blade 150 and the distal cuttingedge 166 define a broad top surface 154 for effecting tissue. The broadtop surface 154 of the blade 150 has a width “W” that is substantiallygreater than a thickness “T”. In one embodiment, the cutting edge 168extends from the proximal end 132 to the distal end 134 of the treatmentregion 158. The blade 150 also comprises a dull, smooth, or curvedlateral coagulating edge 164 positioned laterally along the side of thetreatment region 158 opposite the lateral cutting edge 168. In oneembodiment, the coagulating edge 164 extends from the proximal end 132to the distal end 134 of the treatment region 158. The coagulating edge164 may be used for different tissue effects other than coagulation, forexample. In one example, the flat tip distal cutting edge 166 or thelateral cutting edge 168 of the ultrasonic blade 150 is suitable toremove muscle tissue from bone while the atraumatic surface 162 glidesagainst the bone. The clinician may select either one of the cuttingedges 166, 168 or the atraumatic surface 162 for different tissueeffects. The ultrasonic blade 150 may be fabricated from a materialsuitable for transmission of ultrasonic energy as previously describedwith respect to the ultrasonic blade 120.

FIGS. 12-15 illustrate one embodiment of an ultrasonic blade 180. Theultrasonic blade 180 is generally well-suited for cutting, coagulating,and reshaping tissue. In one embodiment the ultrasonic blade 180 may beconfigured as an ultrasonic surgical elevator blade generallywell-suited to separate muscle tissue from bone. Nevertheless, theultrasonic blade 180 may be employed in various other therapeuticprocedures. FIG. 12 is a side view of the ultrasonic blade 180. FIG. 13is a top view of the ultrasonic blade 180. FIG. 14 is a cross-sectionalview of the ultrasonic blade 180 taken along line 14-14 in FIG. 12. FIG.15 is a top perspective view of the ultrasonic blade 180.

In the embodiment illustrated in FIGS. 12-15, the ultrasonic blade 180comprises a blade body 182 having a generally flat planar top surface184 and a generally flat planar bottom surface 186. The top and bottomsurfaces 184, 186 are substantially parallel and extend along thelongitudinal central axis 127. The blade body 182 may comprise asubstantially elongated treatment region, generally designated as 188,and a neck or transition portion 190 that protrudes from a proximal end132 of the treatment region 188. The neck portion 190 may be attached tothe ultrasonic transmission waveguide 104 by a stud, weld, glue, quickconnect, or other known attachment methods, for example. In alternativeembodiments, the ultrasonic blade 180 and the ultrasonic transmissionwaveguide 104 may be formed as a single unitary body. In eitherconfiguration, the ultrasonic transmission waveguide 104 amplifies themechanical vibrations transmitted to the ultrasonic blade 180 as is wellknown in the art. Accordingly, the ultrasonic blade 180 is adapted tocouple to the ultrasonic surgical instrument 100, which may be employedwith the above-described ultrasonic surgical instruments 100, which maybe employed in the above-described ultrasonic system 10. In oneembodiment, the ultrasonic blade 180 and the ultrasonic transmissionwaveguide 104 may be formed as a single unitary body.

The ultrasonic blade 180 comprises the substantially flat planartreatment region 188 to effect tissue. The treatment region 188comprises the generally flat planar top surface 184 and the generallyflat planar bottom surface 186. A notch 192 (hook shaped in theillustrated embodiment) is defined at the distal end 134 of thetreatment region 188. The notch 192 extends inwardly into the blade body182. The notch 192 comprises a cutting edge 194. A first straightlateral cutting edge 196 is positioned on the distal end 134 of thetreatment region 188. A second straight lateral cutting edge 198 ispositioned laterally along the along the side of the treatment region188 between the notch 192 and the proximal end 132. A dull, smooth, orcurved coagulating edge 200 is positioned laterally along the side ofthe treatment region 188 opposite the lateral cutting edge 198. Thedull, smooth, or curved coagulating edge 200 is substantially arcuateabout axis 135. The blade 180 and the lateral cutting edge 198 define abroad top surface 184. The broad top surface 184 of the blade 184 has awidth “W” that is substantially greater than a thickness “T”. In oneembodiment, the curved edge 200 extends from the proximal end 132 to thedistal end 134 of the treatment region 188. The coagulating edge 200 maybe used different tissue effects other than coagulation, for example. Inone example, the cutting edges 194, 196, 198 of the ultrasonic blade 180may be employed to remove muscle tissue from bone while the coagulatingedge 200 may be used for coagulation. The notch cutting edge 194 assistsin cutting tissue. For example, the notch cutting edge 194 allows forfaster tissue cutting in avascular tissue or may aid in entering jointcapsules. The ultrasonic blade 180 may be fabricated from a materialsuitable for transmission of ultrasonic energy as previously describedwith respect to the ultrasonic blade 120.

FIGS. 16-19 illustrate one embodiment of an ultrasonic blade 210. Theultrasonic blade 210 is generally well-suited for cutting, coagulating,and reshaping tissue. In one embodiment the ultrasonic blade 210 may beconfigured as an ultrasonic surgical elevator blade generallywell-suited to separate muscle tissue from bone. Nevertheless, theultrasonic blade 210 may be employed in various other therapeuticprocedures. FIG. 16 is a side view of the ultrasonic blade 210. FIG. 17is a top view of the ultrasonic blade 210. FIG. 18 is an end-sectionalview of the ultrasonic blade 210 taken along line 18-18 in FIG. 16. FIG.19 is a top perspective view of the ultrasonic blade 210.

In the embodiment illustrated in FIGS. 16-19, the ultrasonic blade 210comprises a blade body 212 having a generally flat planar top surface214 and a generally flat planar bottom surface 216. The top and bottomsurfaces 212, 214 are substantially parallel and extend along thelongitudinal central axis 127. The blade body 212 may comprise asubstantially elongated treatment region, generally designated as 218,and a neck or transition portion 220 that protrudes from a proximal end132 of the treatment region 218. The neck portion 220 may be attached tothe ultrasonic transmission waveguide 104 by a stud, weld, glue, quickconnect, or other known attachment methods, for example. In alternativeembodiments, the ultrasonic blade 210 and the waveguide 104 may beformed as a single unitary body. In either configuration, the ultrasonictransmission waveguide 104 amplifies the mechanical vibrationstransmitted to the ultrasonic blade 210 as is well known in the art.Accordingly, the ultrasonic blade 210 is adapted to couple to theultrasonic transmission waveguide 104 of the surgical instrument 100,which may be employed with the above-described ultrasonic system 10. Inone embodiment, the ultrasonic blade 210 and the ultrasonic transmissionwaveguide 104 may be formed as a single unitary body.

The ultrasonic blade 210 comprises the substantially flat planartreatment region 218 to effect tissue. The treatment region 218comprises the generally flat planar top surface 214 and the generallyflat planar bottom surface 216. A first atraumatic flat edge 222 may bepositioned on the tip at the distal end 134 of the ultrasonic blade 210for bone contact and atraumatic use along the bone region as well as tocharacterize the blade 210. The blade 210 and the distal atraumatic edge222 define a broad top surface 214 for effecting tissue. The top surface214 of the blade 210 has a width “W” that is substantially greater thana thickness “T” of the blade 210. The flat atraumatic edge 222 at thetip of the distal end 134 of the ultrasonic blade 210 may be normal tothe longitudinal central axis 127 of the ultrasonic blade 210 and may beemployed for benchmarking measurements of the displacement of the distalend 134, for example. This may be employed to make measurements and tocharacterize the ultrasonic blade 210. A smooth atraumatic surface 228that is substantially arcuate about axis 135 may be provided at thedistal end 134 for bone contact and atraumatic use along the boneregion. Cutting edges 224, 226 may be disposed laterally along bothsides of the treatment region 218. The ultrasonic blade 210 may befabricated from a material suitable for transmission of ultrasonicenergy as previously described with respect to the ultrasonic blade 120.

FIG. 20 is a top perspective view of one embodiment of an ultrasonicblade 230. The ultrasonic blade 230 is generally well-suited forcutting, coagulating, and reshaping tissue. In one embodiment theultrasonic blade 230 may be configured as an ultrasonic surgicalelevator blade generally well-suited to separate muscle tissue frombone. Nevertheless, the ultrasonic blade 230 may be employed in variousother therapeutic procedures. The ultrasonic blade 230 has a blade body232 that has a generally flat planar tapered top surface portion 234, agenerally flat planar bottom surface 238 (FIG. 21), and an offset edgeportion 236 with a cutting edge 239 well-suited for dissecting tissueagainst bone. The ultrasonic blade 230 may be fabricated from a materialsuitable for transmission of ultrasonic energy as previously describedwith respect to the ultrasonic blade 120. The blade body 232 maycomprise a substantially elongated treatment region, generallydesignated as 240, and a neck or transition portion 242 that protrudesfrom a proximal end 132 of the treatment region 240. The neck portion242 may be attached to the ultrasonic transmission waveguide 104 by astud, weld, glue, quick connect, or other known attachment methods, forexample. In alternative embodiments, the ultrasonic blade 230 and thewaveguide 104 may be formed as a single unitary body. In eitherconfiguration, the ultrasonic transmission waveguide 104 amplifies themechanical vibrations transmitted to the ultrasonic blade 230 as is wellknown in the art. Accordingly, the ultrasonic blade 230 is adapted tocouple to the ultrasonic surgical instrument 100, which may be employedwith the above-described ultrasonic system 10.

FIG. 21 illustrates a use of one embodiment of the ultrasonic blade 230shown in FIG. 20. The ultrasonic blade 230 comprises the generallyplanar treatment region 240 with a generally flat planar top surface234, a generally flat planar bottom surface 238, and an offset edgeportion 236 with a cutting edge 239. The cutting edge 239 is suitable todissect muscle tissue 244 from a bone 246.

The ultrasonic blades 120, 150, 180, 210, 230 described above each havea length “L” that is substantially equal to an integral multiple ofone-half system wavelengths (λ/2). The distal end 134 of the ultrasonicblades 120, 150, 180, 210, 230 may be disposed near an antinode in orderto provide the maximum longitudinal excursion of the distal end 134.When the transducer assembly is energized, the distal end 134 of theultrasonic blade 120, 150, 180, 210, 230 may be configured to move inthe range of, for example, approximately 10 to 500 microns peak-to-peak,and preferably in the range of about 30 to 150 microns at apredetermined vibrational frequency range. As previously discussed, asuitable vibrational frequency range may be about 20 Hz to 120 kHz and awell-suited vibrational frequency range may be about 30-70 kHz and oneexample operational vibrational frequency may be approximately 55.5 kHz.

Other embodiments may comprise multiple end effectors 50 attacheddistally to a common ultrasonic transmission waveguide 104. The endeffectors 50 may provide a variety of tissue effects that are similar tothose discussed above with respect to the ultrasonic blades 120, 150,180, 210, 230. As discussed above, the ultrasonic blades 120, 150, 180,210, 230 may be separable (and of differing composition) from thewaveguide 104, and coupled by, for example, a stud, weld, glue, quickconnect, or other known methods. A quick connect coupling may providelower cost and ease of use of multiple ultrasonic blades 120, 150, 180,210, 230 in one procedure.

As described above, an end effector or blade of an ultrasonic surgicalinstrument can be vibrated along a longitudinal axis to treat tissue,for example. In various circumstances, such instruments can bepreferably configured such that they do not vibrate in any otherdirection, such as axes which are transverse to the longitudinal axis,for example. Such transverse vibration may make the surgical instrumentinefficient and may require additional power to operate the surgicalinstrument, for example. In at least one circumstance, such transversevibration may be created and/or amplified by an imbalanced asymmetricalconfiguration of the blade. In various embodiments of the presentinvention, an end effector or blade of an ultrasonic surgical instrumentcan be configured such that such transverse vibration is reduced oreliminated. For example, in at least one embodiment, the blade caninclude an asymmetrical configuration which can be balanced with respectto at least one axis which is transverse to the longitudinal vibrationalaxis of the surgical instrument, as described in greater detail below.

In various embodiments, referring to FIGS. 56-59, an ultrasonic surgicalinstrument blade, such as blade 680, for example, can include blade body682 having a generally flat top surface, or side, 684 and a generallyflat bottom surface, or side, 686. Although surfaces, or sides, 684 and686 can be generally flat or planar, they can comprise any suitableconfiguration including curved and/or curvilinear configurations, forexample. The top and bottom surfaces 684, 686 can be substantiallyparallel and can extend along the longitudinal or central axis 127. Theblade body 682 may comprise a substantially elongated treatment region,generally designated as 688, and a neck or transition portion 690 thatprotrudes from a proximal end 632 of the treatment region 688. The neckportion 690 may be attached to the ultrasonic transmission waveguide 104(FIG. 1) by a stud, weld, glue, quick connect, or other known attachmentmethods, for example. In alternative embodiments, the ultrasonic blade680 and the ultrasonic transmission waveguide 104 may be formed as asingle unitary body. In either configuration, the ultrasonictransmission waveguide 104 can amplify the mechanical vibrationstransmitted to the ultrasonic blade 680 as is well known in the art.

In various embodiments, blade 680 can include a notch 692 (hook shapedin the illustrated embodiment) which is defined at the distal end 634 ofthe treatment region 688. The notch 692 can extend inwardly into theblade body 682, as illustrated in FIGS. 57 and 59, wherein the notch 692can comprise a cutting edge 694 configured to incise tissue, forexample. In various embodiments, referring to FIG. 58, the blade 680 canfurther include cutting edge 696 which can also be configured to incisetissue, for example. In at least one embodiment, the cross-section ofblade 680, again referring to FIG. 58, can be configured such that blade680 is balanced, or at least substantially balanced, with respect toaxis 669. In various embodiments, the cross-section can be defined by aplane, such as plane 673, for example, wherein plane 673 can beperpendicular to longitudinal axis 127 and wherein axis 669 can liewithin the plane 673. In at least one embodiment, the cross-section ofblade 680 can include a body, or central, portion 675 and a cutting, orstep, portion 679, extending from central portion 675. In variousembodiments, axis 669 may be referred to as a centerline of the blade,or a portion of the blade, although such use is not intended tocommunicate that the blade, or a portion of the blade, is necessarilysymmetrical. Often, such a reference can be used to refer to an axis, ordatum, which is utilized to determine or measure whether a symmetricaland/or asymmetrical blade, or a portion of a blade, is balanced withrespect thereto.

In various embodiments, referring to the cross-section of blade 680illustrated in FIG. 60, the sides of central portion 675 can be definedby surfaces 684 and 686, for example, wherein surfaces 684 and 686 candefine a width (w) therebetween. Although the width of central portion675 is substantially constant in the illustrated exemplary embodiment,the width of central portion 675 can have any suitable configuration,including configurations which comprise identical, or at leastsubstantially identical, portions on the opposite sides of transverseaxis 669, for example. In at least one such embodiment, central portion675 can include a first mass M_(B1) positioned on a first side oftransverse axis 669 and a second mass M_(B2) positioned on a second sideof said transverse axis, wherein M_(B1) can be equal, or at leastsubstantially equal, to M_(B2). In various embodiments, again referringto FIG. 60, M_(B1) can comprise the area defined by l₁ and w/2 and,similarly, M_(B2) can comprise the area defined by l₂ and w/2. In atleast one embodiment, l₁ can equal, or at least substantially equal, l₂.In various alternative embodiments, however, M_(B1) may not be equal toM_(B2). In at least one such embodiment, l₁ may not equal l₂. In variousembodiments, though, the mass of blade 680 may be balanced in anothermanner as described in greater detail below.

In various embodiments, referring to FIG. 60, step portion 679 of thecross-section can comprise first surface 681 and second surface 683,wherein cutting edge 696 can be positioned intermediate first surface681 and second surface 683. In at least one embodiment, step portion 679can include, similar to the above, a first mass M_(S1), defined by A₁,positioned on the first side of axis 669 and a second mass M_(S2),defined by A₂, positioned on the opposite, or second, side of axis 669,wherein M_(S1) can be equal, or at least substantially equal, to M_(S2).In at least one such embodiment, step portion 679 can include a centerof gravity 685, wherein center of gravity 685 can be positioned alongtransverse axis 669. Although various embodiments having a symmetricalstep portion 679 are possible, step portion 679 can include anasymmetric configuration with respect to transverse axis 669. In atleast one such embodiment, cutting edge 696 may not lie along, or beco-planar with, axis 669 wherein, as a result, blade 680 can include acutting edge which is positioned closer to one of sides 684 and 686without creating a mass imbalance with respect to axis 669. In at leastone embodiment, referring to FIG. 60, cutting edge 696 can be positioneda distance x with respect to second side 686, for example, such thatblade 680 is balanced as described in greater detail below. Owing to thecloser proximity of the cutting edge with respect to one side of theblade, the cutting edge may be more visible to the surgeon therebyfacilitating the proper use of the surgical instrument.

In various embodiments, further to the above, M_(S1) may not be equal toM_(S2). In at least one such embodiment, though, the masses of centralportion 675 and step portion 679, for example, can be arranged such thatthe mass of blade 680 is still balanced with respect to transverse axis669, for example. More particularly, M_(S1), M_(S2), M_(B1), and M_(B2)can be selected such that M_(B1)+M_(S1) is equal, or at leastsubstantially equal, to M_(B2)+M_(S2). In such embodiments, as a result,the total mass of blade 680 on the first side of axis 669 can be equal,or at least substantially equal, to the total mass of blade 680 on thesecond side of axis 669. Furthermore, in various embodiments, the massof blade 680 can be arranged such that the moment of force and themoment of inertia of masses M_(S1), M_(S2), M_(B1), and M_(B2) arebalanced as well. Generally, the moment of force of a mass isproportional to the product of the mass and the distance between thecenter of gravity of the mass and a datum, or axis. Also, generally, themoment of inertia of a mass is proportional to the product of the massand the square of the distance between the center of gravity of the massand a datum, or axis. Referring to the illustrated embodiment of FIG.60, masses M_(S1), M_(S2), M_(B1), and M_(B2) can be positioned so as tobalance, or at least substantially balance, the moment of force and themoment of inertia of blade 680 with respect to transverse axis 669, forexample.

In various embodiments, again referring to FIG. 60, step portion 679, asdescribed above, can include first and second surfaces and a cuttingedge 696 positioned therebetween. In at least one embodiment, stepportion 679 can further include an edge height, s, which can define thedistance between cutting edge 696 and first portion 697 of step portion679. More particularly, in at least one embodiment, step portion 679 caninclude first portion 697 and cutting portion 699 which are separated bydatum 695, wherein edge height s can define the distance between the topof first portion 697, i.e., cutting edge 696, and datum 695. Statedanother way, referring to FIG. 60A, edge height s can be defined as thedistance between the top of a right triangle defined by area A₄ and thetop of a right triangle defined by the combined areas of A₁ and A₃. Inat least one embodiment, further to the above, A₁ can equal A₂, and A₂can equal A₃+A₄. In various embodiments where second surface 683 isparallel to axis 669, the edge height s can equal the length of secondsurface 683. In various other embodiments where second surface 683 isnot parallel to axis 669, the edge height s can equal the length of theprojection of second surface 683 onto axis 669. In various embodiments,cutting edge 696 can lie in a first plane 693, datum 695 can lie in asecond plane which is parallel to the first plane, and wherein the stepheight s can define the distance between the first and second planes.

In various embodiments, first surface 681 and second surface 683 can bearranged such that an angle α, or edge angle, is defined therebetweenwherein the edge angle can be any suitable angle such as approximately35 degrees or approximately 65 degrees, for example. During variousexperimental uses of such surgical blades, it was observed that surgicalblades having smaller edge angles, i.e., angles closer to zero degrees,transected tissue faster than surgical blades having larger edge angles,i.e., angles closer to 90 degrees. It was also observed, though, thatsuch blades were to able to seal, or produce hemostasis within, theedges of the tissue as the tissue was being transected regardless of theedge angle selected. Such a result was deemed to be surprising and,advantageously, it is believed that the edge angle of the bladesdisclosed herein can be selected to facilitate a desired cutting ratewithout affecting the hemostasis of the tissue. Furthermore, it was alsodetermined by the experimental uses of such surgical blades that arelationship for producing hemostasis within porcine tissue cancomprise:

1.26−0.0102*a−1.14*h+8.14w

wherein a represents the longitudinal amplitude of the blade, wherein wrepresents the width of the blade, similar to the above, and wherein hrepresents the height of the blade. In various embodiments, thisrelationship for producing hemostasis can be equated to zero, values fortwo of variables a, h, and w can be selected or input into therelationship, and the relationship can then be utilized to determine avalue for the third variable. In at least one circumstance, thisrelationship was used to determine a suitable range of widths for theblade, w, which can be between approximately 0.040″ and approximately0.070″, depending on the level of hemostasis required from a particularblade. A width of approximately 0.060″ was selected for one actualexample.

In at least one embodiment, second surface 683 of step portion 679 canbe parallel, or at least substantially parallel, to first side 684and/or second side 686 of central portion 675. In various embodiments,first surface 681 can lie within a plane which is transverse to secondsurface 683 and first side 684, for example. Although portions of theexemplary embodiment of step portion 679 in FIG. 60 are illustrated asright triangles having straight sides, step portion 679 can include anysuitable configuration which is balanced, or at least substantiallybalanced, with respect to transverse axis 669, for example. In at leastone embodiment, such balancing can be achieved by positioning the centerof gravity of the step portion along the centerline of the blade. Invarious embodiments, a blade, such as blade 680, for example, can bebalanced such that the relationship of:

$\begin{matrix}{{{\frac{x^{2}}{2*\tan \; \alpha} + {\frac{( {w - x} )}{2}( {\frac{x}{\tan \; \alpha} - s} )} - {( \frac{w}{2} )^{2}\frac{1}{\tan \; \alpha}\mspace{14mu} {or}}},{{correspondingly}\text{:}}}{{\frac{x^{2}}{2}*\tan^{- 1}\alpha} + {\frac{( {w - x} )}{2}( {{x*\tan^{- 1}\alpha} - s} )} - {( \frac{w}{2} )^{2}\tan^{- 1}\alpha}}} & (1)\end{matrix}$

is equal to, or at least substantially equal to, zero, wherein w is thewidth of the body portion of the blade, such as central portion 675, forexample, wherein α is the edge angle defined between the first andsecond surfaces of the step portion, such as surfaces 681 and 683, forexample, wherein s is the edge height of the step portion which can bedefined as outlined above, and wherein x is the distance between a sideof the body portion, such as second side 686, and the cutting edge ofthe step portion, such as cutting edge 696, for example.

In various embodiments, suitable values for variables w, s, and α can beselected and relationship (1) can be manipulated to determine a valuefor variable x. In at least one such embodiment, relationship (1) isequated to zero and the selected values for variables w, s, and α aresubstituted into relationship (1) to determine the value for variable x.In such circumstances, variable x is dependent upon the selection of thevalues for w, s, and α. If a blade, such as blade 680, for example, isconstructed in accordance with the selected values of w, s, and α andthe determined value for x, then blade 680 will be balanced, or at leastsubstantially balanced, with respect to transverse axis 669, forexample. As outlined above, the values for variables w, s, and α can beselected for various reasons. For example, the value for variable w,i.e., the width of the body portion of the blade, can be selected suchthat the blade can fit through an endoscope, for example. In variousembodiments, the value for variables s and α, i.e., the height and edgeangle of step portion 679, can be selected to improve or optimize themanufacturability of the blade. In addition to or in lieu of the above,the values for variable w, s, and/or α can be selected to optimize thecutting performance of the blade, for example.

Although relationship (1) may be utilized to set variable x as adependent variable, relationship (1) may be utilized to set at least oneof the other above-described variables as a dependent variable. In atleast one such embodiment, for example, relationship (1) can be equatedto zero and selected values for variables w, s, and x can be substitutedinto relationship (1) to determine a value for variable α. Similarly,relationship (1) can be equated to zero and selected values forvariables w, α, and x can be substituted into relationship (1) todetermine a value for variable s, for example. A similar approach can beundertaken to determine a value for variable w. Further to the above, invarious embodiments, an ultrasonic surgical blade can be configured suchthat, for any given values of s and w, the relationship of:

A*x²*tan⁻¹ α+B*x*tan⁻¹ α+C*tan⁻¹ α+D*x+E  (2)

is equal, or at least substantially equal, to zero, wherein A, B, C, D,and E are constants. In various alternative embodiments, an ultrasonicsurgical blade can be configured such that, for any given values of sand α, the relationship of:

A*x²+B*x+C*x*w+D*w+E*w²+F  (3)

is equal, or at least substantially equal, to zero, wherein A, B, C, D,E, and F are constants. In various further embodiments, an ultrasonicsurgical blade can be configured such that, for any given values of wand α, the relationship of:

A*x²+B*x+C*x*s+D*s+E  (4)

is equal, or at least substantially equal, to zero, wherein A, B, C, D,and E are constants.

In various embodiments, the above-described approaches for balancing anultrasonic surgical blade can be utilized to balance, or at leastsubstantially balance, various alternative surgical blades as outlinedin greater detail below. In at least one embodiment, owing to therelationship between mass and kinetic energy, the energy imparted bysuch blades can also be balanced. More specifically, if the mass of ablade is balanced with respect to a datum or centerline of a blade, thekinetic energy produced by the blade, when it is motivated, will also bebalanced with respect to the datum or centerline. In such circumstances,as a result, the surgical blade can be configured to deliver a uniformenergy profile to the targeted tissue, for example. In variousembodiments, a balanced, or at least substantially balanced, blade canprovide a uniform, or at least substantially uniform, pressure profileto the targeted tissue. In at least one embodiment, a blade can beconsidered to be substantially balanced if the mass on the first side ofthe cross-section centerline is within approximately 10 percent of themass on the second side of the centerline. In such embodiments, althoughthe blade is not mass balanced, any transverse vibrations produced bythe unbalanced blade may not substantially affect the performance of theblade. In at least one embodiment, a blade can be consideredsubstantially balanced if the cutting edge, such as cutting edge 696,for example, is positioned within approximately 10 percent of thecalculated distance for x, for example. Further to the above, althoughmethods of balancing the mass of a blade with respect to one axis havebeen described herein, such methods can be utilized to balance the massof a blade with respect to two or more axes.

In at least one embodiment, referring to FIG. 61, blade 780 can includea central portion 775 having first side 784 and second side 786. Blade780 can further include two step portions 779 which, in variousembodiments, can be positioned on opposite sides of central portion 775.In such embodiments, as a result, blade 780 can comprise two cuttingedges 796 which can be configured to transect tissue, for example. Invarious embodiments, further to the above, each step portion 779 can bebalanced with respect to axis 769, wherein axis 769 can be transverse tolongitudinal axis 127. In various alternative embodiments, although notillustrated, step portions 779 can be arranged such that, although eachstep portion 779 may be imbalanced with respect to axis 769, stepportions 779 can balance, or offset, one another. In at least oneadditional embodiment, referring to FIG. 62, blade 880 can includecentral portion 875 and two step portions 879 wherein, similar to theabove, portions 875 and 879 can be balanced with respect to transverseaxis 869. In at least one further embodiment, referring to FIG. 63,blade 980 can include a central portion 975 having first side 984 andsecond side 986. Blade 980 can further include two step portions 979wherein, similar to the above, portions 975 and 979 can be balanced withrespect to transverse axis 969. In at least one more embodiment,referring to FIG. 64, blade 1080 can include central portion 1075 andtwo step portions 1079 wherein portions 1075 and 1079 can be balancedwith respect to transverse axis 1069.

FIGS. 22-24 illustrate one embodiment of an ultrasonic blade 250comprising a protective sheath 252. The ultrasonic blade 250 isgenerally well-suited for cutting, coagulating, and reshaping tissue.The protective sheath 252 is generally well suited for glidinglyengaging the surface of the bone to prevent damage to the bone and theultrasonic blade 250 while the ultrasonic blade 250 removes muscletissue from the bone and to dissipate thermal energy generated by theultrasonic blade 250. FIG. 22 illustrates a partial cross-sectional viewof one embodiment of an ultrasonic blade 250 comprising a protectivesheath 252 taken along the longitudinal axis. FIG. 23 is a bottom viewof the ultrasonic blade 250 taken along line 23-23. FIG. 24 is across-sectional view of the ultrasonic blade 250 and the protectivesheath 252. The ultrasonic blade 250 comprises a body 254 having asubstantially planar top surface 256 a generally rounded cutting edge258 and an atraumatic surface 259 for bone contact and atraumatic usealong the bone region configured to prevent the cutting edge 136 fromcutting into bone tissue. In one embodiment the cutting edge 258 may beconfigured as an ultrasonic surgical elevator blade generallywell-suited to separate muscle tissue from bone. A lateral cutting edge264 suitable for dissecting tissue is positioned on one side of the body254 and an atraumatic edge 266 suitable to coagulate tissue may bepositioned laterally along an opposite side of the body 254. The bodyalso comprises a generally flat planar bottom surface 268 adjacent tothe protective sheath 252. An air gap 262 may separate the bottomsurface 268 from the protective sheath 252 for cooling purposes, forexample. The protective sheath 252 comprises a substantially arcuatelateral bottom surface 260 with a flat portion in the center thereof.

FIG. 25 illustrates a use of one embodiment of an ultrasonic surgicalinstrument 270 removing muscle tissue 244 from bone 246. The ultrasonicsurgical instrument 270 comprises the ultrasonic blade 250 describedabove. The ultrasonic blade 250 comprises the atraumatic bone protectivesheath 252. As used herein, atraumatic means designed to avoid injury.In one embodiment, the atraumatic bone protective sheath 252 extendslongitudinally below the ultrasonic blade 250 to the handpiece housingof the ultrasonic surgical instrument 270 to act between the bottomsurface of the ultrasonic blade 268 and the bone 246 to avoid injuringthe bone 246 while coagulating, reshaping, or removing muscle tissue 244from the bone 246 as described above. The air gap 262 provides a pathfor irrigation fluid to pass between the bottom surface 268 of theultrasonic blade 250 and the protective sheath 252 to dissipate thermalenergy generated by the ultrasonic blade 250 while cutting. In oneembodiment, the protective sheath 252 may be rigidly and fixedlyattached or mounted to the bottom surface 268 of the ultrasonic blade250 in any suitable manner to reduce design complexity and cost. Inother embodiments, the protective sheath 252 may be fixedly mounted toother substantially rigid portions of the ultrasonic surgical instrument270. In alternative embodiments, the protective sheath 252 may be userdeployable (e.g., retractable).

The protective sheath 252 reduces thermal heating effects that mayresult from the ultrasonic blade 250 contacting the bone 246. Theprocess of removing the muscle tissue 244 from the bone 246 duringposterior spine access may be a lengthy procedure. Accordingly, there isa concern that the high temperatures may build and cause breakage of theultrasonic blade 250, spread of excessive lateral thermal heating,damage to the bone 246, damage to the muscle 244, and/or damage to nervetissue. Accordingly, the bottom surface 268 of the ultrasonic blade 250is shielded or protected by the protective sheath 252 and can restagainst the surface of the bone 246 while the active portion or thecutting edge 258 of the ultrasonic blade 250 applies energy to themuscle tissue 244, resulting in good surgical technique of dissectingmuscle tissue from bone (e.g., the spine). This protective sheath 252also shields the ultrasonic blade 250 from contacting metal retractorsand thus minimizes the risk of breaking the blade 250. Reducing the riskof breaking the ultrasonic blade 250 reduces instrument exchange duringa surgical procedure because there is less concern for retractinginstruments to avoid breaking the ultrasonic blade 250. In addition, theprotective sheath 252 may enable more directed energy between the bladeand a clamp arm (not shown).

The protective sheath 252 may be formed of any suitable polymericmaterial and may be formed on or attached to the ultrasonic blade 250using a variety of techniques. Generally, the protective sheath 252 maybe formed of any material suitable to shield the ultrasonic blade 250from contacting bone or metal objects while cutting and minimizing therisk that of breaking the ultrasonic blade 250. In addition, theprotective sheath 252 may be formed of a material and may be attached tothe ultrasonic blade 250 in a manner that is suitable to decrease thethermal energy created by the ultrasonic blade 250 to spread from thebottom surface 268 thereof. In one embodiment, the protective sheath 252may be formed by coating the bottom surface 268 of the ultrasonic blade250 with a polymeric material. The protective sheath 252 may be formedof a variety of high temperature lubricious polymers. For example, theprotective sheath 252 may be formed of any number of fluorinatedpolymers such as Tetrafluoroethylene or Polytetrafluoroethylene, such asTeflon® by DuPont. In another embodiment, the protective sheath 252 maybe formed as separate rigid polymeric component permanently attached(e.g., affixed, mounted) to the bottom surface 268 of the ultrasonicblade 250. The protective sheath 252 may be attached to the bottomsurface 268 of the ultrasonic blade 250 with physical snaps, adhesives,and/or insert/molding. In yet another embodiment, the protective sheath252 may be formed as a separate rigid polymeric component mounted to arigid portion of the ultrasonic instrument 270 and shield the bottomsurface 268 of the ultrasonic blade 250 without physically contactingthe bottom surface 268 of the ultrasonic blade 250. This provides theair gap 262 between the bottom surface 268 of the ultrasonic blade 250and the separate rigid polymeric protective sheath 252. The air gap 262enables irrigation fluid to travel between the protective sheath 252 andthe bottom surface 268 of the ultrasonic blade 250 to assist in coolingthe blade. In one embodiment, irrigation may be provided within theprotective sheath to assist in cooling the ultrasonic blade 250 fromultrasonically induced thermal effects. For example, in one embodiment aprotective sheath may be configured to act as an irrigation conduitalong the bottom surface of the ultrasonic blade to provide directedirrigation for surgical regions as well as providing a cooling effect tothe ultrasonic blade during use (FIGS. 52-55). In various otherembodiments, the protective sheath 252 may be user deployable and/orretractable by the user. Thus the user may deploy the protective sheath252 to shield the bottom surface 268 of the ultrasonic blade 150 fromthe bone 246 or may retract the protective sheath 252 when desired toenable back-cutting. In other embodiments, the protective sheath 252 maybe configured to assist in the mechanical dissection or removal of themuscle tissue 244 from the bone 246. For example, the protective sheath252 may be configured in the shape and style to accommodate aconventional curette or cobb blade with sharp cutting edges 258, 264.The sheath also may be employed as a fulcrum along the bottom surface268 of the ultrasonic blade 250 while still enabling distal and lateraltissue effects by exposing the cutting edge 258 of the ultrasonic blade250.

FIG. 26 illustrates a use of one embodiment of the ultrasonic surgicalblade 230 shown in FIGS. 20, 21 comprising one embodiment of aprotective sheath 272. The protective sheath 272 is positioned adjacentto the bottom surface 238 of the ultrasonic surgical blade 230. Theprotective sheath 272 protects the bone 246 as the cutting edge 239dissects the muscle tissue 244 from the bone 246. An air gap 274 betweenthe protective sheath 272 and the bottom surface 238 of the ultrasonicblade 230 provides a path for irrigation fluid to pass therebetween todissipate thermal energy generated by the ultrasonic blade 230 whilecutting. The protective sheath 272 may be formed of any polymericmaterial as previously discussed with respect to FIGS. 22-25.

FIGS. 27-31 illustrate one embodiment of an ultrasonic surgicalinstrument 280 comprising an end effector 304. FIG. 27 is a topperspective view of one embodiment of the ultrasonic surgical instrument280. FIG. 28 is a cross-sectional view of the ultrasonic surgicalinstrument 280 shown in FIG. 27 taken along the longitudinal axis of theultrasonic surgical instrument 280. FIG. 29 is a bottom view of theultrasonic surgical instrument 280 taken along lines 29-29. FIG. 30 is across-sectional view of the ultrasonic surgical instrument 280 takenalong lines 30-30. FIG. 31 is cross-sectional view of the ultrasonicsurgical instrument 280 taken along lines 31-31. With reference now toFIGS. 27-31, the ultrasonic surgical instrument 280 comprises an outertubular member or outer tube 282 that extends from the handpieceassembly 456 (FIGS. 41-44). The outer tube 282 has a substantiallycircular cross-section and a longitudinal opening or aperture 302 toreceive an inner tubular member or inner tube 312. The outer tube 282has a substantially circular cross-section and may be fabricated fromstainless steel. It will be recognized that the outer tube 282 may beconstructed from any suitable material and may have any suitablecross-sectional shape. Located at the distal end of the ultrasonicsurgical instrument 280 is an end effector 304 for performing varioustasks, such as, for example, grasping tissue, cutting tissue and thelike. It is contemplated that the end effector 304 may be formed in anysuitable configuration.

The end effector 304 comprises a non-vibrating clamp arm assembly 284,an ultrasonic blade 286, and a protective sheath 288. The clamp armassembly 284 comprises a tissue pad 300. The non-vibrating clamp armassembly 284 is to grip tissue or compress tissue against the ultrasonicblade 286, for example.

The ultrasonic blade 286 is generally well-suited for cutting,coagulating, and reshaping tissue. In one embodiment the ultrasonicblade 286 may be configured as an ultrasonic surgical elevator bladegenerally well-suited to separate muscle tissue from bone. Nevertheless,the ultrasonic blade 286 may be employed in various other therapeuticprocedures. The ultrasonic blade 286 comprises a cutting edge 324 at adistal portion and in other embodiments may comprise one or more lateralcutting edges and/or lateral atraumatic dull, smooth or curved edges.The ultrasonic blade 286 comprises a bottom surface 322 adjacent to theprotective sheath 288 such that the protective sheath 288 shields thebottom surface 322 from contacting other surfaces. The ultrasonic blade286 may be coupled to the ultrasonic transmission waveguide 104 or maybe formed as a unitary piece therewith. The ultrasonic instrument 280may be employed with the ultrasonic system 10.

The protective sheath 288 is generally well suited for glidinglyengaging the surface of the bone to prevent damage to the bone while theultrasonic blade 286 removes muscle tissue from bone and to dissipatethermal energy generated by the ultrasonic blade 286 while cutting. Inthe embodiment, the protective sheath 288 may be fixedly coupled to theultrasonic blade 286 or to the outer tube 282 and is not userdeployable. An air gap 320 between the bottom surface 322 of theultrasonic blade 286 and the protective sheath 288 provides a path forirrigation fluid to pass therebetween to dissipate thermal energygenerated by the ultrasonic blade 286. The protective sheath 288comprises the proximal partially circumferentially extending portion 310that overlaps and fixedly engages the outer tube 282. As previouslydiscussed, the proximal partially circumferentially extending portion310 comprises multiple projections 318 to engage apertures 316 formed inthe outer tube 282. In one embodiment, the protective sheath 288 may befixedly attached to the outer sheath 282 by way of the multipleprojections 318 engaging the apertures 316 formed in the outer tube 282.As shown in FIG. 30, the protective sheath 288 comprises a curvedsubstantially arcuate bottom surface 314 to slidingly engage bone. Thecurved bottom surface 314 comprises a convex portion 315 at a distal endand a concave portion 317 at a proximal end. The protective sheath 288may be formed of any polymeric material as previously discussed withrespect to FIGS. 22-25.

The end effector 304 is illustrated in a clamp open position. The clamparm assembly 284 is preferably pivotally mounted to the distal end ofthe outer tube 282 at pivot points 290A, B such that the clamp armassembly 284 can rotate in the direction shown by arrows 294, 298. Theclamp arm assembly 284 preferably includes clamp arms 306A, B andcorresponding pivot pins 291A, B on either side to engage the pivotpoints 290A, B. The distal end of the inner tube 312 comprises fingersor flanges 313A and 313B (not shown) that extend therefrom. The fingers313A, B have corresponding openings 313A and 313B (not shown) to receiveposts 315A and 315B (not shown) of the clamp arms 306A, B. When theinner tube 312 is moved axially, the fingers 313A, B move axiallyforwardly or rearwardly and engage the corresponding posts 315A, B ofthe clamp arms 306A, B to open and close the clamp arm assembly 284. Forexample, when the inner tube 312 moves axially rearwardly or isretracted towards the proximal end in the direction indicated by arrow292, the clamp arm assembly 284 opens in the direction indicated byarrow 294. When the inner tube 312 moves axially or is advanced towardsto the distal end in the direction indicated by arrow 296 the clamp armassembly 284 closes in the direction indicated by arrow 298. The outertube 282 remains fixed and the apertures 316 are configured to receivethe projecting members 318 from the partially circumferentiallyextending portion 310 of the protective sheath 288. The proximalpartially circumferentially extending portion 310 of the protectivesheath 288 is thus fixedly mounted to the outer tube 282. In oneembodiment, the proximal partially circumferentially extending portion310 of the protective sheath 288 may be formed of similar materials asthe protective sheath 288 or may be formed of other substantially rigidmaterials.

The clamp arm 306 includes the tissue pad 300 attached thereto forsqueezing tissue between the ultrasonic blade 286 and the clamp armassembly 300. The tissue pad 300 is preferably formed of a polymeric orother compliant material and engages the ultrasonic blade 286 when theclamp arm 306 is in its closed position. Preferably, the tissue pad 300is formed of a material having a low coefficient of friction but whichhas substantial rigidity to provide tissue-grasping capability, such as,for example, TEFLON, a trademark name of E. I. Du Pont de Nemours andCompany for the polymer polytetraflouroethylene (PTFE). The tissue pad300 may be mounted to the clamp arm 300 by an adhesive, or preferably bya mechanical fastening arrangement. Serrations 308 are formed in theclamping surfaces of the tissue pad 300 and extend perpendicular to theaxis of the ultrasonic blade 286 to allow tissue to be grasped,manipulated, coagulated and cut without slipping between the clamp arm306 and the ultrasonic blade 286.

FIGS. 32-35 are cross-sectional views of various embodiments ofultrasonic surgical instruments 350, 352, 354, 356 taken along thelongitudinal axis. The ultrasonic surgical instruments 350, 352, 354,356 comprise respective fixedly attached protective sheaths 358, 364,370, 376. As previously discussed, fixedly attached means that theprotective sheaths are not deployable and remain in the position shownin FIGS. 32-35 during use of the instruments 350, 352. As shown in FIGS.32-35, the ultrasonic surgical instrument 350, 352, 354, 356 eachcomprise the outer tube 282 that extends from a handpiece assembly(e.g., the handpiece assembly 60 shown in FIG. 1). The outer tube 282has a substantially circular cross-section and a longitudinal opening oraperture 302 to receive the inner tube 312. Located at the distal end ofthe ultrasonic surgical instrument 350 is an end effector 304 forperforming various tasks, such as, for example, grasping tissue, cuttingtissue and the like. It is contemplated that the end effector 304 may beformed in any suitable configuration. The ultrasonic surgical instrument350, 352, 354, 356 may be employed with the ultrasonic system 10.

The end effector 304 comprises the non-vibrating clamp arm assembly 284,an ultrasonic blade 286, and a protective sheath 354. The clamp armassembly 284 is preferably pivotally attached to the distal end of theouter tube 282 at the pivot point 290. The clamp arm assembly 284comprises a tissue pad 300. As previously discussed, the ultrasonicblade 286 may be coupled to the ultrasonic transmission waveguide 104 ormay be formed as a unitary piece therewith and may be actuated by theultrasonic system 10.

The protective sheaths 358, 364, 370, 376 are generally well suited forglidingly engaging the surface of the bone to prevent damage to the bonewhile the ultrasonic blade 286 removes muscle tissue from the bone andto dissipate thermal energy generated by the ultrasonic blade 286 whilecutting. The protective sheaths 358, 364, 370, 376 may be fixedlycoupled to the ultrasonic blade 286 or to the outer tube 282 and are notuser deployable. An air gap 320 between the bottom surface 322 of theultrasonic blade 286 and the fixed protective sheaths 358, 364, 370, 376provides a space for irrigation fluid to pass therebetween to dissipatethermal energy generated by the ultrasonic blade 286 while cutting. Inthe embodiments illustrated in FIGS. 32-35, the fixedly mountedprotective sheaths 358, 364, 370, 376 each comprise the proximalpartially circumferentially extending portion 310 that overlaps andfixedly engages the outer tube 282. As previously discussed, theproximal partially circumferentially extending portion 310 comprisesmultiple projections 318 to engage the apertures 316 formed in the outertube 282 and thus the protective sheaths 358, 364, 370, 376 are fixedlysecured within the outer tube 282. The alternative embodiments, thefixed protective sheaths 358, 364, 370, 376 may be attached to an innertube positioned within the outer tube 282. The fixed protective sheaths358, 364, 370, 376 each comprise a distal portion comprising respectivetapered bodies 384, 388, 392, 398 that extend longitudinally beyond thedistal portion of the ultrasonic blade 286 to protect the distal cuttingedge 324 of the ultrasonic blade 286. In other embodiments, the taperedbodies 384, 388, 392, 398 may extend laterally to protect longitudinalportions of the ultrasonic blade 286. The fixed protective sheaths 358,364, 370, 376 each comprise respective substantially planar sheetportions 359, 365, 371, 377 extending longitudinally between the distaltapered bodies 384, 388, 392, 398 and the proximal partiallycircumferentially extending portion 310 to shield the bottom surface 322of the ultrasonic blade 286. The protective sheaths 358, 364, 370, 376may be formed of any polymeric material as previously discussed withrespect to FIGS. 22-25.

As shown in FIG. 32, the fixed protective sheath 358 comprises thetapered body 360 at a distal end that extends longitudinally beyond thedistal end of the ultrasonic blade 286. The tapered body 360 comprises asubstantially planar top surface 362 and a substantially planar bottomsurface 382 that taper from a proximate end to a blunt distal end 384.

As shown in FIG. 33, the fixed protective sheath 364 comprises thetapered body 366 at a distal end that extends longitudinally beyond thedistal end of the ultrasonic blade 286. The tapered body 366 comprises asubstantially planar top surface 368 and a substantially planar bottomsurface 386 that taper from a proximate end to a blunt distal end 388.The substantially planar top and bottom surfaces 368, 386 havecorresponding radiused contoured surfaces that meet the blunt surface388.

As shown in FIG. 34, the fixed protective sheath 370 comprises thetapered body 378 at a distal end that extends longitudinally beyond thedistal end of the ultrasonic blade 286. The tapered body 378 comprises acurved top surface 374 and a curved bottom surface 390 that taper from aproximate end to a sharp distal end 392.

As shown in FIG. 35, the fixed protective sheath 376 comprises thetapered body 378 at a distal end that extends longitudinally beyond thedistal end of the ultrasonic blade 286. The tapered body 378 comprises asubstantially planar top surface 396 and a substantially curved bottomsurface 394 that taper from a proximate end to a sharp distal end 398.

FIGS. 36-37 are cross-sectional views of one embodiment of an ultrasonicsurgical instrument 400 taken along the longitudinal axis. Theultrasonic surgical instrument 400 may be employed with the ultrasonicsystem 10. The ultrasonic surgical instrument 400 comprises a deployableprotective sheath 402. In one embodiment, the deployable protectivesheath 402 may be deployed by a user during a surgical procedure.Deployable means that the deployable protective sheath 402 may beadvanced to a distal end in the direction indicated by arrow 404 to beput into use and may be retracted to a proximate end in the directionindicated by arrow 406 when it is to be taken out of use. The deployableprotective sheath 402 comprises a distal portion 401 that substantiallyshields the bottom surface 322 of the ultrasonic blade 286 when it isdeployed. The deployable protective sheath 402 comprises a proximateportion 403 that extends to the handpiece assembly (e.g., the handpieceassembly 60 shown in FIG. 1) where it is coupled to a protective sheathdeploying and retracting mechanism. The distal portion 401 may be formedslightly thicker then the proximal portion 403. The deployableprotective sheath 402 may be formed of any polymeric material aspreviously discussed with respect to FIGS. 22-25. In one embodiment, theproximal portion 403 may be formed of the same material as the distalportion 401 of the deployable protective sheath 402. In otherembodiments, the proximal portion 403 may be formed of a different moredurable material than the distal portion 401 of the deployableprotective sheath 402 to withstand repeated deployments and retractions.For example, the proximal portion 403 may be formed of metal or otherdurable material to withstand the moderate forces required to hold thedeployable protective sheath 402 in place during deployment, retraction,and use.

The ultrasonic surgical instrument 400 comprises the outer tube 282 thatextends from the handpiece assembly 456. The outer tube 282 has asubstantially circular cross-section and a longitudinal opening oraperture 302 to receive the inner tube 312. Located at the distal end ofthe ultrasonic surgical instrument 350 is an end effector 304 forperforming various tasks, such as, for example, grasping tissue, cuttingtissue and the like. It is contemplated that the end effector 304 may beformed in any suitable configuration. The end effector 304 comprises thenon-vibrating clamp arm assembly 284, an ultrasonic blade 286, and thedeployable protective sheath 402. The clamp arm assembly 284 ispreferably pivotally attached to the distal end of the outer tube 282 atthe pivot point 290. The clamp arm assembly 284 comprises a tissue pad300. As previously discussed, the ultrasonic blade 286 may be coupled tothe ultrasonic transmission waveguide 104 or may be formed as a unitarypiece therewith.

When the deployable protective sheath 402 is advanced in the directionindicated by arrow 404, it is generally well suited for glidinglyengaging the surface of the bone to prevent damage to the bone while theultrasonic blade 286 removes muscle tissue from the bone and todissipate thermal energy generated by the ultrasonic blade 286 whilecutting. The deployable protective sheath 402 also is well suited toshield the bottom surface of the blade 322 from contact with otherobjects. The deployable protective sheath 402 may be retracted in thedirection indicated by arrow 406 when it is not needed. When thedeployable protective sheath 402 is deployed, the air gap 320 betweenthe bottom surface 322 of the ultrasonic blade 286 and the protectivesheath 402 provides a space for irrigation fluid to pass therebetween todissipate thermal energy generated by the ultrasonic blade 286 whilecutting. In one embodiment, the deployable protective sheath 402 mayretract within the inner tube 312.

FIGS. 38-39 are cross-sectional views of one embodiment of an ultrasonicsurgical instrument 410 taken along the longitudinal axis. Theultrasonic surgical instrument 410 comprises a deployable protectivesheath 412. In one embodiment, the deployable protective sheath 412 maybe deployed by a user during a surgical procedure. Deployable means thatthe deployable protective sheath 412 may be advanced to a distal end inthe direction indicated by arrow 404 to be put in use and may beretracted to a proximate end in the direction indicated by arrow 406 tobe put out of use. The deployable protective sheath 402 comprises adistal portion 407 that substantially covers the bottom surface 418 ofthe ultrasonic blade 414 when it is deployed. The deployable protectivesheath 412 comprises a proximate portion 405 that extends to a handpieceassembly (e.g., the handpiece assembly 60 shown in FIG. 1) where it iscoupled to a protective sheath deploying and retracting mechanism. Thedistal portion 407 may be formed slightly thicker then the proximalportion 405. The distal portion comprises a vertically extendingprojection 420 to protect the cutting edge 416 of the ultrasonic blade414. The projection 420 is adapted to engage and compress the bottomsurface of the ultrasonic blade 414 when it is retracted. The deployableprotective sheath 402 may be formed of any polymeric material aspreviously discussed with respect to FIGS. 22-25. In one embodiment, theproximal portion 405 may be formed of the same material as the distalportion 407 of the deployable protective sheath 412. In otherembodiments, the proximal portion 405 may be formed of a different moredurable material than the distal portion 407 of the deployableprotective sheath 412 to withstand repeated deployments and retractions.For example, the proximal portion 405 of the deployable protectivesheath 412 may be formed of metal or other durable material to withstandthe moderate forces required to hold the deployable protective sheath412 in place during deployment, retraction, and use.

The ultrasonic surgical instrument 410 comprises the outer tube 282 thatextends from the handpiece assembly 456. The outer tube 282 has asubstantially circular cross-section and a longitudinal opening oraperture 302 to receive the inner tube 312. Located at the distal end ofthe ultrasonic surgical instrument 350 is an end effector 304 forperforming various tasks, such as, for example, grasping tissue, cuttingtissue and the like. It is contemplated that the end effector 304 may beformed in any suitable configuration. The end effector 304 comprises thenon-vibrating clamp arm assembly 284, an ultrasonic blade 414 with adistal chisel-shaped cutting edge 416, and the deployable protectivesheath 412. The clamp arm assembly 284 is preferably pivotally attachedto the distal end of the outer tube 282 at the pivot point 290. Theclamp arm assembly 284 comprises a tissue pad 300. As previouslydiscussed, the ultrasonic blade 286 may be coupled to the ultrasonictransmission waveguide 104 or may be formed as a unitary piecetherewith.

When the deployable protective sheath 412 is advanced in the directionindicated by arrow 404, it is generally well suited for gliding alongthe surface of the bone to prevent damage to the bone while theultrasonic blade 414 removes muscle tissue from the bone. The deployableprotective sheath 412 may be retracted in the direction indicated byarrow 406 when it is not needed. When the deployable protective sheath412 is deployed, the air gap 320 between the bottom surface 418 of theultrasonic blade 414 and the protective deployable sheath 412 provides aspace for irrigation fluid to pass therebetween. The protectivedeployable sheath 412 retracts inside the inner tube 312.

FIG. 40 is cross-sectional view of one embodiment of an ultrasonicsurgical instrument 430 taken along the longitudinal axis. Theultrasonic surgical instrument 430 may be employed with the ultrasonicsystem 10. The ultrasonic surgical instrument 430 comprises a fixedlyattached protective sheath 432. As previously discussed, fixedlyattached means that the protective sheath is not deployable and remainsin the position shown in FIG. 40 for the usable life of the instrument430. As shown in FIG. 40, the ultrasonic surgical instrument 430comprises the outer tube 282 that extends from the handpiece assembly456. The outer tube 282 has a substantially circular cross-section and alongitudinal opening or aperture 302 to receive the inner tube 312.Located at the distal end of the ultrasonic surgical instrument 350 isan end effector 304 for performing various tasks, such as, for example,grasping tissue, cutting tissue and the like. It is contemplated thatthe end effector 304 may be formed in any suitable configuration.

The end effector 304 comprises the non-vibrating clamp arm assembly 284,an ultrasonic blade 286, and a protective sheath 432. The clamp armassembly 284 is preferably pivotally attached to the distal end of theouter tube 282 at the pivot points 290A, B. The clamp arm assembly 284comprises a tissue pad 300. As previously discussed, the ultrasonicblade 286 may be coupled to the ultrasonic transmission waveguide 104 ormay be formed as a unitary piece therewith.

The protective sheath 432 is generally well suited for glidinglyengaging the surface of the bone to prevent damage to the bone while theultrasonic blade 286 removes muscle tissue from the bone and todissipate thermal energy generated by the ultrasonic blade 286 whilecutting. The protective sheath 432 is also well suited to shield thebottom surface 322 of the blade 286. The protective sheath 432 may befixedly coupled to the ultrasonic blade 286 or to the outer tube 282 byway of projections 318 (FIGS. 27-31) and apertures 316 and is not userdeployable. An air gap 320 between the bottom surface 322 of theultrasonic blade 286 and the fixed protective sheath 432 provides aspace for irrigation fluid to pass therebetween to dissipate thermalenergy generated by the ultrasonic blade 286 while cutting. The fixedprotective sheath 432 comprises the proximal partially circumferentiallyextending portion 310 that overlaps and fixedly engages the outer tube282. As previously discussed, the proximal partially circumferentiallyextending portion 310 comprises the multiple projections 318 to engagethe apertures 316 formed in the outer tube 282. The fixed protectivesheath 432 is attached to the outer tube 282. The fixed protectivesheath 432 comprises discrete projections or bumps 434 formed on a topsurface 436 thereof. There may be one or multiple bumps 434 formed onthe top surface 436 of the protective sheath 432. The bumps 434 decreasethe contact surface area between the ultrasonic blade 286 and theprotective sheath 432, which may occur during a procedure when theprotective sheath is used as a fulcrum. This may reduce the heat orthermal energy generated by the ultrasonic blade 286 and the load on theultrasonic blade 286. The protective sheath 432 may be formed of anypolymeric material as previously discussed with respect to FIGS. 22-25.

FIGS. 41-43 illustrate one embodiment of an ultrasonic system 400. FIG.41 is a side view of the ultrasonic system 400. One embodiment of theultrasonic system 400 comprises the ultrasonic signal generator 12coupled to the ultrasonic transducer 14, a hand piece housing 452, andan end effector 304 (shown in FIG. 27) forming an ultrasonic instrument456. The ultrasonic instrument 456 comprises a curved lever member 454coupled to the protective sheath 402 to move the protective sheath 402axially. The ultrasonic instrument 456 also comprises a slideable member458B coupled to the inner tube 312. The slideable member 458B movesaxially within a slot that defines walls 460B formed in the hand piecehousing 452 to actuate the end effector 304.

FIG. 42 is a cross-sectional side view of the ultrasonic system 456shown in FIG. 41 and a cross-sectional view of various tube assembliesto couple the hand piece housing 452 with an end effector. As shown inFIG. 42, the curved lever member 454 is pivotally mounted to the handpiece housing 452 at pivot point 462 such that it can rotate in thedirection indicated by arrows 463A, B. Link members 464A and 464B (notshown) are pivotally coupled at a proximate end to pivot points 466A and466B (not shown) and at a distal end to pivot points 468A and 468B (notshown). When the curved lever member 454 is rotated about the pivotpoint 462 in the direction indicated by arrow 463A the sheath 402 movesaxially in the direction indicated by arrow 465A in its deployedposition. When the curved lever member 454 is moved in the directionindicated by arrow 463B the sheath 402 moves axially in the directionindicated by arrow 465B n its retracted position.

FIG. 43 is a bottom cross-sectional view of the ultrasonic instrument456 shown in FIG. 41. As shown in FIG. 43, the slideable members 458A, Bare held in a locked position by respective springs 472A, B which engageand compress the slideable members 458A, B against an interior portionof the hand piece housing 452. The interior portion of the hand piecehousing 452 comprises rows of serrated edges 474A, B formed along innerportions of the walls 460A, B defined by the slot. Notched members 480A,B are mounted to flanges formed on the slideable members 458A, B and areconfigured to engage the respective serrated edges 474A, B formed in therespective walls 460A, B. Bodies 470A, B are formed integrally with theinner tube 312 or are attached to thereto. When a force is applied inthe direction indicated by arrows 476, B against the respective springs472A, B, the slideable members 458A, B can be moved axially as indicatedby arrows 478A, B. Thus the inner tube 312 moves axially to actuate theclamp arm assembly 284 of the end effector 304.

In alternative embodiments, the ultrasonic instrument 456 may be adaptedand configured such that the curved lever member 454 is coupled to theinner tube 312 and the slideable members 458A, B are coupled to theprotective sheath 402. Accordingly, rotating the curved lever member 454moves the inner tube 312 axially to actuate the end effector 304. Andthe slideable members 458A, B can be used to axially deploy and retractthe protective sheath 402.

FIGS. 44-51 illustrate one embodiment of an ultrasonic system 500. FIG.44 is a side view of the ultrasonic instrument 506 with the deployableprotective sheath 402 in a stowed or retracted position. FIG. 45 is atop view of the ultrasonic instrument 506 with the deployable protectivesheath 402 in the stowed or retracted position taken along line 45-45 inFIG. 44. FIG. 46 is a side view of the ultrasonic instrument 506 withthe deployable protective sheath 402 in a deployed position. FIG. 47 isa top view of the ultrasonic instrument 506 in the deployed positiontaken along line 47-47 in FIG. 46.

With reference to FIGS. 44-47, one embodiment of the ultrasonicinstrument 500 is coupled to an ultrasonic signal generator 12 andcomprises an ultrasonic transducer 14, a hand piece housing 502, and anend effector 504 forming an ultrasonic instrument 506. The ultrasonicinstrument 506 comprises a slideable member 508 coupled to thedeployable protective sheath 402 in any suitable manner as previouslydiscussed. The slideable member 508 moves axially within a slot 510formed in the hand piece housing 502 to actuate or deploy/retract thedeployable protective sheath 402. The slideable member 508 is shown inthe deployable protective sheath 402 retracted or stowed position. Whenthe slideable member 508 moves axially in the direction indicated byarrow 514 the deployable protective sheath 402 also moves axially in thesame direction to its retracted or stowed position. When the slideablemember 508 moves axially in the direction indicated by arrow 516 thedeployable protective sheath 402 also moves axially in the samedirection to its deployed position. Once deployed, the deployableprotective sheath 402 may be locked in place with any suitable lockingmechanism. An air gap 518 provides a path for irrigation fluid to coolthe ultrasonic blade 512 while cutting. The end effector 504 comprisesan ultrasonic blade 512 coupled to the ultrasonic transducer 14 by theultrasonic transmission waveguide 104 as previously discussed. The fixedouter tube 282 (or sheath) shields the surgeon and the patient fromunintended contact with the ultrasonic blade 512 and the ultrasonictransmission waveguide 104.

FIG. 48 is a more detailed side view of the ultrasonic instrument 506with the deployable protective sheath 402 in a stowed or retractedposition. FIG. 49 is a more detailed top view of the ultrasonicinstrument 506 with the protective sheath 402 in the stowed or retractedposition taken along line 49-49 in FIG. 48. FIG. 50 is a more detailedside view of the ultrasonic instrument 506 with the deployableprotective sheath 402 in a deployed position. FIG. 51 is a more detailedtop view of the ultrasonic instrument 506 in the deployed position takenalong line 51-51 in FIG. 50.

With reference to FIGS. 44-51, the deployable protective sheath 402 isuser deployable by moving the slideable member 508 in the directionindicated by arrow 516. The distal end of the deployable protectivesheath 402 may be formed of any polymeric material as previouslydiscussed with respect to FIGS. 22-25. The proximal end of thedeployable protective sheath 402 may be formed of metal or other durablematerial to withstand the moderate forces required to hold thedeployable protective sheath 402 in place during deployment, retraction,and use.

FIG. 50 shows the deployable protective sheath 402 in the deployedposition in a substantially relaxed state as indicated by the air gap518 between the deployable protective sheath 402 and the ultrasonicblade 512. Thus, in a stress free state, the deployable protectivesheath 402 does not contact the ultrasonic blade 512. When thedeployable protective sheath 402 is used as a fulcrum, however, it maycontact the ultrasonic blade 512 for some period of time. However, whenthe pressure is released on the ultrasonic instrument 500, thedeployable protective sheath 402 is sufficiently resilient to return toits initial position, thus restoring the air gap 518 between theprotective sheath 412 and the ultrasonic blade 512. If needed, aseparate spring may be added to the deployable protective sheath 402 toensure that it no longer contacts the ultrasonic blade 512 once thepressure is released. In the illustrated embodiment, the deployableprotective sheath 402 is shown to be smaller than the outline of theultrasonic blade 512. This enables the user to cut tissue with thedistal tip and both edges of the ultrasonic blade 512 when thedeployable protective sheath 402 is deployed. In alternate embodiments,the deployable protective sheath 402 may also cover some or all of thethree edges of the ultrasonic blade 512.

FIGS. 52-55 illustrate one embodiment of an ultrasonic surgicalinstrument 550 comprising an end effector 552. The ultrasonic surgicalinstrument may be employed with the ultrasonic system 10. FIG. 52 is atop perspective view of one embodiment of the ultrasonic surgicalinstrument 550. FIG. 53 is a partial cross-sectional view of theultrasonic surgical instrument 550 shown in FIG. 52 taken along thelongitudinal axis of the ultrasonic surgical instrument 550. FIG. 54 isa cross-sectional view of the ultrasonic surgical instrument 550 takenalong lines 54-54 shown in FIG. 53. FIG. 55 is a top view of theultrasonic surgical instrument 550.

With reference now to FIGS. 52-55, the ultrasonic surgical instrument550 comprises an outer member or outer tube 282 that extends from thehandpiece assembly 60 or 456 (FIG. 1 or FIGS. 41-44). The outer tube 282has a substantially circular cross-section and a longitudinal opening oraperture 302 to receive an inner member or an inner tube 312. The outertube 282 has a substantially circular cross-section and may befabricated from stainless steel. It will be recognized that the outertube 282 may be constructed from any suitable material and may have anysuitable cross-sectional shape. Located at the distal end of theultrasonic surgical instrument 550 is an end effector 552 for performingvarious tasks, such as, for example, grasping tissue, cutting tissue andthe like. It is contemplated that the end effector 304 may be formed inany suitable configuration.

The end effector 552 comprises a non-vibrating clamp arm assembly 284,an ultrasonic blade 286, and a protective sheath 554. The end effector552 is illustrated in a clamp open position and operates in a mannerdiscussed above. The clamp arm assembly 284 comprises a tissue pad 300.The non-vibrating clamp arm assembly 284 is to grip tissue or compresstissue against the ultrasonic blade 286, for example. The protectivesheath 552 defines a chamber 556 in fluid communication with irrigationchannels or tubes 558A, B to receive irrigation fluid from theirrigation channels 558A, B. The irrigation channels 558A, B couple toconventional irrigation devices by way of ports 560A, B (not shown) atthe proximate end of the ultrasonic instrument 550. The irrigationchannels 558A, B deliver irrigation fluid to the chamber 556 todissipate thermal energy generated by the ultrasonic blade 286 whilecutting and carrying away pieces cut bone and tissue. Irrigation may becontrolled manually by way of a control button on the handpiece orautomatically wherein each time the ultrasonic instrument 550 is poweredon a irrigation fluid release cam may be activated to release theirrigation fluid.

The ultrasonic blade 286 is generally well-suited for cutting,coagulating, and reshaping tissue. In one embodiment the ultrasonicblade 286 may be configured as an ultrasonic surgical elevator bladegenerally well-suited to separate muscle tissue from bone. Nevertheless,the ultrasonic blade 286 may be employed in various other therapeuticprocedures. The ultrasonic blade 286 comprises a cutting edge 324 at adistal portion and may comprise cutting edges extending longitudinallyalong the sides of the ultrasonic blade 286. The ultrasonic blade 286comprises a bottom surface 322 adjacent to the protective sheath 554.The ultrasonic blade 286 may be coupled to the ultrasonic transmissionwaveguide 104 or may be formed as a unitary piece therewith.

The protective sheath 554 is generally well suited for glidinglyengaging the surface of the bone to prevent damage to the bone while theultrasonic blade 286 removes muscle tissue from the bone and todissipate thermal energy generated by the ultrasonic blade 286 whilecutting. The protective sheath 554 may be fixedly coupled to theultrasonic instrument 550 or may be user deployable. In the illustratedembodiment, the protective sheath 550 is fixedly mounted to the outertube 282 as previously discussed. The protective sheath 288 comprisesthe proximal partially circumferentially extending portion 310 thatoverlaps and fixedly engages the outer tube 282. As previouslydiscussed, the proximal partially circumferentially extending portion310 comprises multiple projections to engage the apertures 316 formed inthe outer tube 282. When fixedly attached, the protective sheath 554 maybe attached to the outer tube 282. When the protective sheath 554 isdeployed, it may be attached to an inner tube received within the innertube 312 that is slidingly engaged to a deployment mechanism on thehandpiece portion of the ultrasonic instrument 550 as previouslydiscussed. The protective sheath 554 comprises a bottom surface 560 toslidingly engage bone. The protective sheath 554 may be formed of anypolymeric material as previously discussed with respect to FIGS. 22-25.

The devices disclosed herein can be designed to be disposed of after asingle use, or they can be designed to be used multiple times. In eithercase, however, the device can be reconditioned for reuse after at leastone use. Reconditioning can include any combination of the steps ofdisassembly of the device, followed by cleaning or replacement ofparticular pieces, and subsequent reassembly. In particular, the devicecan be disassembled, and any number of the particular pieces or parts ofthe device can be selectively replaced or removed in any combination.Upon cleaning and/or replacement of particular parts, the device can bereassembled for subsequent use either at a reconditioning facility, orby a surgical team immediately prior to a surgical procedure. Thoseskilled in the art will appreciate that reconditioning of a device canutilize a variety of techniques for disassembly, cleaning/replacement,and reassembly. Use of such techniques, and the resulting reconditioneddevice, are all within the scope of the present application.

Preferably, the various embodiments described herein will be processedbefore surgery. First, a new or used instrument is obtained and ifnecessary cleaned. The instrument can then be sterilized. In onesterilization technique, the instrument is placed in a closed and sealedcontainer, such as a plastic or TYVEK bag. The container and instrumentare then placed in a field of radiation that can penetrate thecontainer, such as gamma radiation, x-rays, or high-energy electrons.The radiation kills bacteria on the instrument and in the container. Thesterilized instrument can then be stored in the sterile container. Thesealed container keeps the instrument sterile until it is opened in themedical facility.

It is preferred that the device is sterilized. This can be done by anynumber of ways known to those skilled in the art including beta or gammaradiation, ethylene oxide, steam.

Although various embodiments have been described herein, manymodifications and variations to those embodiments may be implemented.For example, different types of end effectors may be employed. Also,where materials are disclosed for certain components, other materialsmay be used. The foregoing description and following claims are intendedto cover all such modification and variations.

Any patent, publication, or other disclosure material, in whole or inpart, that is said to be incorporated by reference herein isincorporated herein only to the extent that the incorporated materialsdoes not conflict with existing definitions, statements, or otherdisclosure material set forth in this disclosure. As such, and to theextent necessary, the disclosure as explicitly set forth hereinsupersedes any conflicting material incorporated herein by reference.Any material, or portion thereof, that is said to be incorporated byreference herein, but which conflicts with existing definitions,statements, or other disclosure material set forth herein will only beincorporated to the extent that no conflict arises between thatincorporated material and the existing disclosure material.

1. A surgical blade for a surgical instrument, the surgical instrumenthaving a transducer configured to produce vibrations along alongitudinal axis at a predetermined frequency, the surgical bladecomprising: a body portion comprising a first side, a second side, and awidth defined between said first and second sides; a step portionextending from said body portion, wherein said step portion comprises afirst surface, a second surface, and a cutting edge situatedintermediate said first and second surfaces, wherein said second surfaceextends between a first plane including said cutting edge and a secondplane which is parallel to said first plane, wherein said first surfaceis not parallel to said second surface, wherein said first and secondsurfaces are oriented such that there is an angle defined therebetween,wherein said blade is configured such that the relationship of:${\frac{x^{2}}{2}*\tan^{- 1}\alpha} + {\frac{( {w - x} )}{2}( {{x*\tan^{- 1}\alpha} - s} )} - {( \frac{w}{2} )^{2}\tan^{- 1}\alpha}$is substantially equal to zero; wherein w is said width of said bodyportion; wherein s is the distance between said first plane and saidsecond plane; wherein α is said angle defined between said first andsecond surfaces of said step portion; and wherein x is the distancebetween said second side of said body portion and said cutting edge. 2.The surgical blade of claim 1, wherein said body portion includes acenterline, wherein said step portion includes a center of gravitypositioned along said centerline, and wherein said cutting edge is notpositioned along said centerline.
 3. The surgical blade of claim 2,wherein said second surface is substantially parallel to saidcenterline.
 4. The surgical blade of claim 1, wherein said body portionincludes a centerline, wherein said step portion includes a center ofgravity positioned along said centerline, and wherein said step portionis asymmetric with respect to said centerline.
 5. The surgical blade ofclaim 1, wherein said relationship is equal to zero.
 6. A surgical bladefor a surgical instrument, the surgical instrument having a transducerconfigured to produce vibrations along a longitudinal axis at apredetermined frequency, the surgical blade comprising: a body portioncomprising a first side, a second side, and a width (w) defined betweensaid first and second sides; a step portion extending from said bodyportion, wherein said step portion comprises a first surface, a secondsurface, and a cutting edge situated intermediate said first and secondsurfaces, wherein said second surface extends between a first planeincluding said cutting edge and a second plane which is parallel to saidfirst plane, wherein said first plane and said second plane areseparated by a distance s, wherein said first surface is not parallel tosaid second surface, wherein said first and second surfaces are orientedsuch that there is an angle (α) defined therebetween, and wherein asecond distance (x) is defined between said second side of said bodyportion and said cutting edge.
 7. The surgical blade of claim 6, whereinsaid blade is configured such that, for any given values of s and w, therelationship of:A*x²*tan⁻¹ α+B*x*tan⁻¹ α+C*tan⁻¹ α+D*x+E is substantially equal to zero,and wherein A, B, C, D, and E are constants.
 8. The surgical blade ofclaim 6, wherein said blade is configured such that, for any givenvalues of s and α, the relationship of:A*x²+B*x+C*x*w+D*w+E*w²+F is substantially equal to zero, and wherein A,B, C, D, E, and F are constants.
 9. The surgical blade of claim 6,wherein said blade is configured such that, for any given values of wand α, the relationship of:A*x²+B*x+C*x*s+D*s+E is substantially equal to zero, and wherein A, B,C, D, and E are constants.
 10. A surgical blade for a surgicalinstrument, the surgical instrument having a transducer configured toproduce vibrations along a longitudinal axis at a predeterminedfrequency, the surgical blade comprising: a distal end; a proximal end;and a cross-section situated intermediate said distal end and saidproximal end, wherein said cross-section is defined by a plane which isperpendicular to the longitudinal axis, wherein said cross-section isfurther defined by a centerline which lies in the plane, and whereinsaid cross-section comprises: a center portion; and a cutting portionextending from said center portion, wherein said cutting portioncomprises a center of gravity which is positioned along said centerline,and wherein said cutting portion further comprises a cutting edge whichis not positioned along said centerline.
 11. The surgical blade of claim10, wherein said cutting portion comprises a first surface and a secondsurface, wherein said cutting edge is situated intermediate said firstand second surfaces, wherein said first surface is not parallel to saidsecond surface, wherein said first and second surfaces are oriented suchthat there is an angle defined therebetween.
 12. The surgical blade ofclaim 11, wherein said center portion includes a first side, a secondside, and a width defined between said first and second sides, whereinsaid second surface of said cutting portion extends between a firstplane including said cutting edge and a second plane which is parallelto said first plane, wherein said blade is configured such that therelationship of:${\frac{x^{2}}{2}*\tan^{- 1}\alpha} + {\frac{( {w - x} )}{2}( {{x*\tan^{- 1}\alpha} - s} )} - {( \frac{w}{2} )^{2}\tan^{- 1}\alpha}$is substantially equal to zero; wherein w is said width of said centerportion; wherein s is the distance between said first plane and saidsecond plane; wherein α is said angle defined between said first andsecond surfaces of said cutting portion; and wherein x is the distancebetween said second side of said center portion and said cutting edge.13. The surgical blade of claim 12, wherein said relationship is equalto zero.
 14. A method of balancing an ultrasonic instrument having anultrasonically actuated blade, wherein the blade comprises a bodyportion and a step portion extending from the body portion, wherein thebody portion comprises a first side, a second side, and a width definedbetween the first and second sides, wherein the step portion includes afirst surface, a second surface, and a cutting edge situatedintermediate the first and second surfaces, wherein the second surfaceextends between a first plane including the cutting edge and a secondplane which is parallel to the first plane, wherein the first and secondsurfaces are not parallel and are oriented such that there is an angledefined therebetween, the method comprising the steps of: configuring atleast a portion of the blade such that the relationship of:${\frac{x^{2}}{2}*\tan^{- 1}\alpha} + {\frac{( {w - x} )}{2}( {{x*\tan^{- 1}\alpha} - s} )} - {( \frac{w}{2} )^{2}\tan^{- 1}\alpha}$is substantially equal to zero; wherein w is said width of the bodyportion; wherein s is the distance between the first plane and thesecond plane; wherein α is said angle defined between the first andsecond surfaces of the step portion; and wherein x is the distancebetween the second side of the body portion and the cutting edge. 15.The method of claim 14, wherein said configuring step comprises thesteps of: selecting values for w, s, and α such that the blade isconfigured to transect tissue; and solving said relationship for x. 16.The method of claim 14, wherein said configuring step comprises thesteps of: selecting values for w, x, and a such that the blade isconfigured to transect tissue; and solving said relationship for s. 17.The method of claim 14, wherein said relationship is equal to zero. 18.A surgical blade for a surgical instrument, the surgical instrumenthaving a transducer configured to produce vibrations along alongitudinal axis at a predetermined frequency, the surgical bladecomprising: a distal end; a proximal end; and a cross-section situatedintermediate said distal end and said proximal end, wherein saidcross-section is defined by a plane which is perpendicular to thelongitudinal axis, wherein the plane is at least partially defined by atransverse axis which is perpendicular to the longitudinal axis, andwherein the cross-section comprises: a body portion having a first mass(M_(B1)) positioned on a first side of said transverse axis and a secondmass (M_(B2)) positioned on a second side of said transverse axis; and astep portion having a first mass (M_(S1)) positioned on said first sideand a second mass (M_(S2)) positioned on said second side, whereinM_(B1)+M_(S1) is substantially equal to M_(B2)+M_(S2), wherein said stepportion further includes a cutting edge, and wherein said cutting edgeis not positioned along said transverse axis.
 19. The surgical blade ofclaim 18, wherein M_(B1)+M_(S1) is equal to M_(B2)+M_(S2).